diff --git a/src/AntShares/Consensus/ConsensusService.cs b/src/AntShares/Consensus/ConsensusService.cs
index cc51aa297b..32cc412b58 100644
--- a/src/AntShares/Consensus/ConsensusService.cs
+++ b/src/AntShares/Consensus/ConsensusService.cs
@@ -104,7 +104,7 @@ private void CheckSignatures()
                 for (int i = 0, j = 0; i < context.Miners.Length && j < context.M; i++)
                     if (context.Signatures[i] != null)
                     {
-                        sc.Add(contract, context.Miners[i], context.Signatures[i]);
+                        sc.AddSignature(contract, context.Miners[i], context.Signatures[i]);
                         j++;
                     }
                 sc.Signable.Scripts = sc.GetScripts();
diff --git a/src/AntShares/Core/SignatureContext.cs b/src/AntShares/Core/SignatureContext.cs
deleted file mode 100644
index c4f7263d78..0000000000
--- a/src/AntShares/Core/SignatureContext.cs
+++ /dev/null
@@ -1,195 +0,0 @@
-using AntShares.Cryptography.ECC;
-using AntShares.IO.Json;
-using AntShares.VM;
-using AntShares.Wallets;
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Reflection;
-using System.Text;
-
-namespace AntShares.Core
-{
-    /// <summary>
-    /// 签名上下文
-    /// </summary>
-    public class SignatureContext
-    {
-        /// <summary>
-        /// 要签名的数据
-        /// </summary>
-        public readonly ISignable Signable;
-        /// <summary>
-        /// 要验证的脚本散列值
-        /// </summary>
-        public readonly UInt160[] ScriptHashes;
-        private readonly byte[][] redeemScripts;
-        private readonly Dictionary<ECPoint, byte[]>[] signatures;
-        private readonly bool[] completed;
-
-        /// <summary>
-        /// 判断签名是否完成
-        /// </summary>
-        public bool Completed
-        {
-            get
-            {
-                return completed.All(p => p);
-            }
-        }
-
-        /// <summary>
-        /// 对指定的数据构造签名上下文
-        /// </summary>
-        /// <param name="signable">要签名的数据</param>
-        public SignatureContext(ISignable signable)
-        {
-            this.Signable = signable;
-            this.ScriptHashes = signable.GetScriptHashesForVerifying();
-            this.redeemScripts = new byte[ScriptHashes.Length][];
-            this.signatures = new Dictionary<ECPoint, byte[]>[ScriptHashes.Length];
-            this.completed = new bool[ScriptHashes.Length];
-        }
-
-        /// <summary>
-        /// 添加一个签名
-        /// </summary>
-        /// <param name="contract">该签名所对应的合约</param>
-        /// <param name="pubkey">该签名所对应的公钥</param>
-        /// <param name="signature">签名</param>
-        /// <returns>返回签名是否已成功添加</returns>
-        public bool Add(Contract contract, ECPoint pubkey, byte[] signature)
-        {
-            for (int i = 0; i < ScriptHashes.Length; i++)
-            {
-                if (ScriptHashes[i] == contract.ScriptHash)
-                {
-                    if (redeemScripts[i] == null)
-                        redeemScripts[i] = contract.RedeemScript;
-                    if (signatures[i] == null)
-                        signatures[i] = new Dictionary<ECPoint, byte[]>();
-                    if (signatures[i].ContainsKey(pubkey))
-                        signatures[i][pubkey] = signature;
-                    else
-                        signatures[i].Add(pubkey, signature);
-                    completed[i] |= contract.ParameterList.Length == signatures[i].Count && contract.ParameterList.All(p => p == ContractParameterType.Signature);
-                    return true;
-                }
-            }
-            return false;
-        }
-
-        /// <summary>
-        /// 从指定的json对象中解析出签名上下文
-        /// </summary>
-        /// <param name="json">json对象</param>
-        /// <returns>返回上下文</returns>
-        public static SignatureContext FromJson(JObject json)
-        {
-            ISignable signable = typeof(SignatureContext).GetTypeInfo().Assembly.CreateInstance(json["type"].AsString()) as ISignable;
-            using (MemoryStream ms = new MemoryStream(json["hex"].AsString().HexToBytes(), false))
-            using (BinaryReader reader = new BinaryReader(ms, Encoding.UTF8))
-            {
-                signable.DeserializeUnsigned(reader);
-            }
-            SignatureContext context = new SignatureContext(signable);
-            JArray scripts = (JArray)json["scripts"];
-            for (int i = 0; i < scripts.Count; i++)
-            {
-                if (scripts[i] != null)
-                {
-                    context.redeemScripts[i] = scripts[i]["redeem_script"].AsString().HexToBytes();
-                    context.signatures[i] = new Dictionary<ECPoint, byte[]>();
-                    JArray sigs = (JArray)scripts[i]["signatures"];
-                    for (int j = 0; j < sigs.Count; j++)
-                    {
-                        ECPoint pubkey = ECPoint.DecodePoint(sigs[j]["pubkey"].AsString().HexToBytes(), ECCurve.Secp256r1);
-                        byte[] signature = sigs[j]["signature"].AsString().HexToBytes();
-                        context.signatures[i].Add(pubkey, signature);
-                    }
-                    context.completed[i] = scripts[i]["completed"].AsBoolean();
-                }
-            }
-            return context;
-        }
-
-        /// <summary>
-        /// 从签名上下文中获得完整签名的合约脚本
-        /// </summary>
-        /// <returns>返回合约脚本</returns>
-        public Script[] GetScripts()
-        {
-            if (!Completed) throw new InvalidOperationException();
-            Script[] scripts = new Script[signatures.Length];
-            for (int i = 0; i < scripts.Length; i++)
-            {
-                using (ScriptBuilder sb = new ScriptBuilder())
-                {
-                    foreach (byte[] signature in signatures[i].OrderBy(p => p.Key).Select(p => p.Value))
-                    {
-                        sb.Push(signature);
-                    }
-                    scripts[i] = new Script
-                    {
-                        StackScript = sb.ToArray(),
-                        RedeemScript = redeemScripts[i]
-                    };
-                }
-            }
-            return scripts;
-        }
-
-        public static SignatureContext Parse(string value)
-        {
-            return FromJson(JObject.Parse(value));
-        }
-
-        /// <summary>
-        /// 把签名上下文转为json对象
-        /// </summary>
-        /// <returns>返回json对象</returns>
-        public JObject ToJson()
-        {
-            JObject json = new JObject();
-            json["type"] = Signable.GetType().FullName;
-            using (MemoryStream ms = new MemoryStream())
-            using (BinaryWriter writer = new BinaryWriter(ms, Encoding.UTF8))
-            {
-                Signable.SerializeUnsigned(writer);
-                writer.Flush();
-                json["hex"] = ms.ToArray().ToHexString();
-            }
-            JArray scripts = new JArray();
-            for (int i = 0; i < signatures.Length; i++)
-            {
-                if (signatures[i] == null)
-                {
-                    scripts.Add(null);
-                }
-                else
-                {
-                    scripts.Add(new JObject());
-                    scripts[i]["redeem_script"] = redeemScripts[i].ToHexString();
-                    JArray sigs = new JArray();
-                    foreach (var pair in signatures[i])
-                    {
-                        JObject signature = new JObject();
-                        signature["pubkey"] = pair.Key.EncodePoint(true).ToHexString();
-                        signature["signature"] = pair.Value.ToHexString();
-                        sigs.Add(signature);
-                    }
-                    scripts[i]["signatures"] = sigs;
-                    scripts[i]["completed"] = completed[i];
-                }
-            }
-            json["scripts"] = scripts;
-            return json;
-        }
-
-        public override string ToString()
-        {
-            return ToJson().ToString();
-        }
-    }
-}
diff --git a/src/AntShares/IO/Json/JObject.cs b/src/AntShares/IO/Json/JObject.cs
index 92113d1bb1..e536b74f2d 100644
--- a/src/AntShares/IO/Json/JObject.cs
+++ b/src/AntShares/IO/Json/JObject.cs
@@ -216,7 +216,7 @@ public static implicit operator JObject(double value)
 
         public static implicit operator JObject(string value)
         {
-            return new JString(value);
+            return value == null ? null : new JString(value);
         }
     }
 }
diff --git a/src/AntShares/Wallets/Contract.cs b/src/AntShares/Wallets/Contract.cs
index f1ea659d80..522bdc55d6 100644
--- a/src/AntShares/Wallets/Contract.cs
+++ b/src/AntShares/Wallets/Contract.cs
@@ -70,6 +70,16 @@ public UInt160 ScriptHash
 
         public int Size => PublicKeyHash.Size + ParameterList.Length.GetVarSize() + ParameterList.Length + RedeemScript.Length.GetVarSize() + RedeemScript.Length;
 
+        public ContractType Type
+        {
+            get
+            {
+                if (IsStandard) return ContractType.SignatureContract;
+                if (IsMultiSigContract()) return ContractType.MultiSigContract;
+                return ContractType.CustomContract;
+            }
+        }
+
         public static Contract Create(UInt160 publicKeyHash, ContractParameterType[] parameterList, byte[] redeemScript)
         {
             return new Contract
@@ -169,6 +179,54 @@ public override int GetHashCode()
             return ScriptHash.GetHashCode();
         }
 
+        private bool IsMultiSigContract()
+        {
+            int m, n = 0;
+            int i = 0;
+            if (RedeemScript.Length < 37) return false;
+            if (RedeemScript[i] > (byte)ScriptOp.OP_16) return false;
+            if (RedeemScript[i] < (byte)ScriptOp.OP_1 && RedeemScript[i] != 1 && RedeemScript[i] != 2) return false;
+            switch (RedeemScript[i])
+            {
+                case 1:
+                    m = RedeemScript[++i];
+                    ++i;
+                    break;
+                case 2:
+                    m = BitConverter.ToUInt16(RedeemScript, ++i);
+                    i += 2;
+                    break;
+                default:
+                    m = RedeemScript[i++] - 80;
+                    break;
+            }
+            if (m < 1 || m > 1024) return false;
+            while (RedeemScript[i] == 33)
+            {
+                i += 34;
+                if (RedeemScript.Length <= i) return false;
+                ++n;
+            }
+            if (n < m || n > 1024) return false;
+            switch (RedeemScript[i])
+            {
+                case 1:
+                    if (n != RedeemScript[++i]) return false;
+                    ++i;
+                    break;
+                case 2:
+                    if (n != BitConverter.ToUInt16(RedeemScript, ++i)) return false;
+                    i += 2;
+                    break;
+                default:
+                    if (n != RedeemScript[i++] - 80) return false;
+                    break;
+            }
+            if (RedeemScript[i++] != (byte)ScriptOp.OP_CHECKMULTISIG) return false;
+            if (RedeemScript.Length != i) return false;
+            return true;
+        }
+
         /// <summary>
         /// 序列化
         /// </summary>
diff --git a/src/AntShares/Wallets/ContractType.cs b/src/AntShares/Wallets/ContractType.cs
new file mode 100644
index 0000000000..8aa6f5fd60
--- /dev/null
+++ b/src/AntShares/Wallets/ContractType.cs
@@ -0,0 +1,9 @@
+namespace AntShares.Wallets
+{
+    public enum ContractType : byte
+    {
+        SignatureContract,
+        MultiSigContract,
+        CustomContract
+    }
+}
diff --git a/src/AntShares/Wallets/SignatureContext.cs b/src/AntShares/Wallets/SignatureContext.cs
new file mode 100644
index 0000000000..3f70fd56ee
--- /dev/null
+++ b/src/AntShares/Wallets/SignatureContext.cs
@@ -0,0 +1,252 @@
+using AntShares.Core;
+using AntShares.Cryptography.ECC;
+using AntShares.IO.Json;
+using AntShares.VM;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Numerics;
+using System.Reflection;
+using System.Text;
+
+namespace AntShares.Wallets
+{
+    /// <summary>
+    /// 签名上下文
+    /// </summary>
+    public class SignatureContext
+    {
+        /// <summary>
+        /// 要签名的数据
+        /// </summary>
+        public readonly ISignable Signable;
+        /// <summary>
+        /// 要验证的脚本散列值
+        /// </summary>
+        public readonly UInt160[] ScriptHashes;
+        private readonly byte[][] redeemScripts;
+        private readonly byte[][][] parameters;
+        private readonly JObject[] temp;
+
+        /// <summary>
+        /// 判断签名是否完成
+        /// </summary>
+        public bool Completed
+        {
+            get
+            {
+                return parameters.All(p => p != null && p.All(q => q != null));
+            }
+        }
+
+        /// <summary>
+        /// 对指定的数据构造签名上下文
+        /// </summary>
+        /// <param name="signable">要签名的数据</param>
+        public SignatureContext(ISignable signable)
+        {
+            this.Signable = signable;
+            this.ScriptHashes = signable.GetScriptHashesForVerifying();
+            this.redeemScripts = new byte[ScriptHashes.Length][];
+            this.parameters = new byte[ScriptHashes.Length][][];
+            this.temp = new JObject[ScriptHashes.Length];
+        }
+
+        public bool Add(Contract contract, int index, byte[] parameter)
+        {
+            int i = GetIndex(contract);
+            if (i < 0) return false;
+            if (redeemScripts[i] == null)
+                redeemScripts[i] = contract.RedeemScript;
+            if (parameters[i] == null)
+                parameters[i] = new byte[contract.ParameterList.Length][];
+            parameters[i][index] = parameter;
+            return true;
+        }
+
+        public bool AddSignature(Contract contract, ECPoint pubkey, byte[] signature)
+        {
+            if (contract.Type == ContractType.MultiSigContract)
+            {
+                int index = GetIndex(contract);
+                if (index < 0) return false;
+                if (redeemScripts[index] == null)
+                    redeemScripts[index] = contract.RedeemScript;
+                if (parameters[index] == null)
+                    parameters[index] = new byte[contract.ParameterList.Length][];
+                if (temp[index] == null) temp[index] = new JArray();
+                JArray array = (JArray)temp[index];
+                JObject obj = new JObject();
+                obj["pubkey"] = pubkey.EncodePoint(true).ToHexString();
+                obj["signature"] = signature.ToHexString();
+                array.Add(obj);
+                if (array.Count == contract.ParameterList.Length)
+                {
+                    List<ECPoint> points = new List<ECPoint>();
+                    {
+                        int i = 0;
+                        switch (contract.RedeemScript[i++])
+                        {
+                            case 1:
+                                ++i;
+                                break;
+                            case 2:
+                                i += 2;
+                                break;
+                        }
+                        while (contract.RedeemScript[i++] == 33)
+                        {
+                            points.Add(ECPoint.DecodePoint(contract.RedeemScript.Skip(i).Take(33).ToArray(), ECCurve.Secp256r1));
+                            i += 33;
+                        }
+                    }
+                    Dictionary<ECPoint, int> dic = points.Select((p, i) => new
+                    {
+                        PublicKey = p,
+                        Index = i
+                    }).ToDictionary(p => p.PublicKey, p => p.Index);
+                    byte[][] sigs = array.Select(p => new
+                    {
+                        Signature = p["signature"].AsString().HexToBytes(),
+                        Index = dic[ECPoint.DecodePoint(p["pubkey"].AsString().HexToBytes(), ECCurve.Secp256r1)]
+                    }).OrderBy(p => p.Index).Select(p => p.Signature).ToArray();
+                    for (int i = 0; i < sigs.Length; i++)
+                        if (!Add(contract, i, sigs[i]))
+                            throw new InvalidOperationException();
+                    temp[index] = null;
+                }
+                return true;
+            }
+            else
+            {
+                int index = -1;
+                for (int i = 0; i < contract.ParameterList.Length; i++)
+                    if (contract.ParameterList[i] == ContractParameterType.Signature)
+                        if (index >= 0)
+                            throw new NotSupportedException();
+                        else
+                            index = i;
+                return Add(contract, index, signature);
+            }
+        }
+
+        /// <summary>
+        /// 从指定的json对象中解析出签名上下文
+        /// </summary>
+        /// <param name="json">json对象</param>
+        /// <returns>返回上下文</returns>
+        public static SignatureContext FromJson(JObject json)
+        {
+            ISignable signable = typeof(SignatureContext).GetTypeInfo().Assembly.CreateInstance(json["type"].AsString()) as ISignable;
+            using (MemoryStream ms = new MemoryStream(json["hex"].AsString().HexToBytes(), false))
+            using (BinaryReader reader = new BinaryReader(ms, Encoding.UTF8))
+            {
+                signable.DeserializeUnsigned(reader);
+            }
+            SignatureContext context = new SignatureContext(signable);
+            JArray scripts = (JArray)json["scripts"];
+            for (int i = 0; i < scripts.Count; i++)
+            {
+                if (scripts[i] != null)
+                {
+                    context.redeemScripts[i] = scripts[i]["redeem_script"].AsString().HexToBytes();
+                    JArray ps = (JArray)scripts[i]["parameters"];
+                    context.parameters[i] = new byte[ps.Count][];
+                    for (int j = 0; j < ps.Count; j++)
+                    {
+                        context.parameters[i][j] = ps[j]?.AsString().HexToBytes();
+                    }
+                    context.temp[i] = scripts[i]["temp"];
+                }
+            }
+            return context;
+        }
+
+        private int GetIndex(Contract contract)
+        {
+            for (int i = 0; i < ScriptHashes.Length; i++)
+                if (ScriptHashes[i].Equals(contract.ScriptHash))
+                    return i;
+            return -1;
+        }
+
+        /// <summary>
+        /// 从签名上下文中获得完整签名的合约脚本
+        /// </summary>
+        /// <returns>返回合约脚本</returns>
+        public Script[] GetScripts()
+        {
+            if (!Completed) throw new InvalidOperationException();
+            Script[] scripts = new Script[parameters.Length];
+            for (int i = 0; i < scripts.Length; i++)
+            {
+                using (ScriptBuilder sb = new ScriptBuilder())
+                {
+                    foreach (byte[] parameter in parameters[i])
+                    {
+                        if (parameter.Length <= 2)
+                            sb.Push(new BigInteger(parameter));
+                        else
+                            sb.Push(parameter);
+                    }
+                    scripts[i] = new Script
+                    {
+                        StackScript = sb.ToArray(),
+                        RedeemScript = redeemScripts[i]
+                    };
+                }
+            }
+            return scripts;
+        }
+
+        public static SignatureContext Parse(string value)
+        {
+            return FromJson(JObject.Parse(value));
+        }
+
+        /// <summary>
+        /// 把签名上下文转为json对象
+        /// </summary>
+        /// <returns>返回json对象</returns>
+        public JObject ToJson()
+        {
+            JObject json = new JObject();
+            json["type"] = Signable.GetType().FullName;
+            using (MemoryStream ms = new MemoryStream())
+            using (BinaryWriter writer = new BinaryWriter(ms, Encoding.UTF8))
+            {
+                Signable.SerializeUnsigned(writer);
+                writer.Flush();
+                json["hex"] = ms.ToArray().ToHexString();
+            }
+            JArray scripts = new JArray();
+            for (int i = 0; i < redeemScripts.Length; i++)
+            {
+                if (redeemScripts[i] == null)
+                {
+                    scripts.Add(null);
+                }
+                else
+                {
+                    scripts.Add(new JObject());
+                    scripts[i]["redeem_script"] = redeemScripts[i].ToHexString();
+                    JArray ps = new JArray();
+                    foreach (byte[] parameter in parameters[i])
+                    {
+                        ps.Add(parameter?.ToHexString());
+                    }
+                    scripts[i]["parameters"] = ps;
+                    scripts[i]["temp"] = temp[i];
+                }
+            }
+            json["scripts"] = scripts;
+            return json;
+        }
+
+        public override string ToString()
+        {
+            return ToJson().ToString();
+        }
+    }
+}
diff --git a/src/AntShares/Wallets/Wallet.cs b/src/AntShares/Wallets/Wallet.cs
index e1a5624ca0..51c8ea907c 100644
--- a/src/AntShares/Wallets/Wallet.cs
+++ b/src/AntShares/Wallets/Wallet.cs
@@ -724,7 +724,7 @@ public bool Sign(SignatureContext context)
                 Account account = GetAccountByScriptHash(scriptHash);
                 if (account == null) continue;
                 byte[] signature = context.Signable.Sign(account);
-                fSuccess |= context.Add(contract, account.PublicKey, signature);
+                fSuccess |= context.AddSignature(contract, account.PublicKey, signature);
             }
             return fSuccess;
         }