diff --git a/example/extension.ts b/example/extension.ts
new file mode 100644
index 0000000..86c260f
--- /dev/null
+++ b/example/extension.ts
@@ -0,0 +1,53 @@
+import { addressToScript } from '@nervosnetwork/ckb-sdk-utils'
+import { Collector } from '../src/collector'
+import { Aggregator } from '../src/aggregator'
+import { Service } from '../src'
+import { generateAddExtensionTx } from '../src/service/cota/extension'
+
+const TEST_PRIVATE_KEY = '0xee56672e70cec79941adc0637c1edb1546a0c39c72eff8c41bc4f1e03bf663b3'
+const TEST_ADDRESS = 'ckt1qyq897k5m53wxzup078jwkucvvsu8kzv55rqqm6glm'
+
+const secp256k1CellDep = (isMainnet: boolean): CKBComponents.CellDep => {
+  if (isMainnet) {
+    return {
+      outPoint: {
+        txHash: '0x71a7ba8fc96349fea0ed3a5c47992e3b4084b031a42264a018e0072e8172e46c',
+        index: '0x0',
+      },
+      depType: 'depGroup',
+    }
+  }
+  return {
+    outPoint: {
+      txHash: '0xf8de3bb47d055cdf460d93a2a6e1b05f7432f9777c8c474abf4eec1d4aee5d37',
+      index: '0x0',
+    },
+    depType: 'depGroup',
+  }
+}
+
+const run = async () => {
+  // True for mainnet and false for testnet
+  const isMainnet = false
+
+  const service: Service = {
+    collector: new Collector({
+      ckbNodeUrl: 'https://testnet.ckb.dev/rpc',
+      ckbIndexerUrl: 'https://testnet.ckb.dev/indexer',
+    }),
+    aggregator: new Aggregator({ registryUrl: 'http://localhost:3050', cotaUrl: 'http://localhost:3030' }),
+  }
+  const ckb = service.collector.getCkb()
+  const extensionLock = addressToScript(TEST_ADDRESS)
+
+  let rawTx = await generateAddExtensionTx(service, extensionLock, BigInt(6000), isMainnet)
+  rawTx.cellDeps.push(secp256k1CellDep(isMainnet))
+
+  const signedTx = ckb.signTransaction(TEST_PRIVATE_KEY)(rawTx)
+  console.log(JSON.stringify(signedTx))
+
+  let txHash = await ckb.rpc.sendTransaction(signedTx, 'passthrough')
+  console.info(`Add cota extension tx has been sent with tx hash ${txHash}`)
+}
+
+run()
diff --git a/package.json b/package.json
index b31ed1c..5fe9f6b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@nervina-labs/cota-sdk",
-  "version": "0.6.6",
+  "version": "0.7.0",
   "description": "The SDK of CoTA",
   "repository": "git@github.com:nervina-labs/cota-sdk-js.git",
   "author": "duanyytop <duanyytop@gmail.com>",
diff --git a/src/aggregator/index.ts b/src/aggregator/index.ts
index 2f786cf..cc2fdd1 100644
--- a/src/aggregator/index.ts
+++ b/src/aggregator/index.ts
@@ -16,6 +16,7 @@ import {
   GetDefineInfoReq,
   GetIssuerInfoReq,
   GetCotaCountReq,
+  ExtensionReq,
 } from '../types/request'
 import {
   ClaimResp,
@@ -37,6 +38,7 @@ import {
   GetDefineInfoResp,
   GetIssuerInfoResp,
   GetCotaCountResp,
+  ExtensionResp,
 } from '../types/response'
 import { Byte32 } from '../types/common'
 
@@ -159,6 +161,10 @@ export class Aggregator {
   async getCotaCount(req: GetCotaCountReq): Promise<GetCotaCountResp> {
     return (await this.baseRPC('get_cota_count', req)) as Promise<GetCotaCountResp>
   }
+
+  async generateExtensionSmt(extension: ExtensionReq): Promise<ExtensionResp> {
+    return (await this.baseRPC('generate_extension_smt', extension)) as Promise<ExtensionResp>
+  }
 }
 
 const convert = (req: GetCotaReq) => ({
diff --git a/src/service/cota/claim-update.ts b/src/service/cota/claim-update.ts
index 78993f7..7d6976b 100644
--- a/src/service/cota/claim-update.ts
+++ b/src/service/cota/claim-update.ts
@@ -35,7 +35,9 @@ export const generateClaimUpdateCotaTx = async (
     nfts,
   }
 
-  const { smtRootHash, claimUpdateSmtEntry, withdrawBlockHash } = await service.aggregator.generateClaimUpdateCotaSmt(claimUpdateReq)
+  const { smtRootHash, claimUpdateSmtEntry, withdrawBlockHash } = await service.aggregator.generateClaimUpdateCotaSmt(
+    claimUpdateReq,
+  )
   const outputsData = [`0x02${smtRootHash}`]
   const cellDeps = [getCotaCellDep(isMainnet)]
   const headerDeps = [`0x${withdrawBlockHash}`]
diff --git a/src/service/cota/cota-meta.ts b/src/service/cota/cota-meta.ts
index 437bd3c..882dc35 100644
--- a/src/service/cota/cota-meta.ts
+++ b/src/service/cota/cota-meta.ts
@@ -1,69 +1,69 @@
-import {  Service } from '../..'
-import { FEE, getCotaTypeScript, getCotaCellDep } from '../../constants'
-import { CotaInfo, Hex } from '../../types'
-import { append0x, utf8ToHex, toSnakeCase } from '../../utils'
-
-const generateCotaMetadata = (cotaInfo: CotaInfo, cotaId: Hex): Hex => {
-  const cotaInfoTemp = {
-    cotaId,
-    ...cotaInfo,
-  }
-  const cotaMeta = {
-    id: 'CTMeta',
-    ver: '1.0',
-    metadata: {
-      target: 'output#0',
-      type: 'cota',
-      data: {
-        version: '0',
-        ...cotaInfoTemp,
-      },
-    },
-  }
-  return append0x(utf8ToHex(JSON.stringify(toSnakeCase(cotaMeta))))
-}
-
-export const generateCotaMetadataTx = async (
-  service: Service,
-  cotaLock: CKBComponents.Script,
-  cotaId: Hex,
-  cotaInfo: CotaInfo,
-  fee = FEE,
-  isMainnet = false,
-) => {
-  const cotaType = getCotaTypeScript(isMainnet)
-  const cotaCells = await service.collector.getCells(cotaLock, cotaType)
-  if (!cotaCells || cotaCells.length === 0) {
-    throw new Error("Cota cell doesn't exist")
-  }
-
-  const cotaCell = cotaCells[0]
-  const inputs = [
-    {
-      previousOutput: cotaCell.outPoint,
-      since: '0x0',
-    },
-  ]
-
-  const outputs = [cotaCell.output]
-  outputs[0].capacity = `0x${(BigInt(outputs[0].capacity) - fee).toString(16)}`
-
-  const cotaOutput = await service.collector.getLiveCell(cotaCell.outPoint)
-  const outputsData = [cotaOutput.data?.content]
-
-  const cellDeps = [getCotaCellDep(isMainnet)]
-
-  const rawTx: any = {
-    version: '0x0',
-    cellDeps,
-    headerDeps: [],
-    inputs,
-    outputs,
-    outputsData,
-    witnesses: [],
-  }
-  rawTx.witnesses = rawTx.inputs.map((_, i) =>
-    i > 0 ? '0x' : { lock: '', inputType: '', outputType: generateCotaMetadata(cotaInfo, cotaId) },
-  )
-  return rawTx
-}
+import { Service } from '../..'
+import { FEE, getCotaTypeScript, getCotaCellDep } from '../../constants'
+import { CotaInfo, Hex } from '../../types'
+import { append0x, utf8ToHex, toSnakeCase } from '../../utils'
+
+const generateCotaMetadata = (cotaInfo: CotaInfo, cotaId: Hex): Hex => {
+  const cotaInfoTemp = {
+    cotaId,
+    ...cotaInfo,
+  }
+  const cotaMeta = {
+    id: 'CTMeta',
+    ver: '1.0',
+    metadata: {
+      target: 'output#0',
+      type: 'cota',
+      data: {
+        version: '0',
+        ...cotaInfoTemp,
+      },
+    },
+  }
+  return append0x(utf8ToHex(JSON.stringify(toSnakeCase(cotaMeta))))
+}
+
+export const generateCotaMetadataTx = async (
+  service: Service,
+  cotaLock: CKBComponents.Script,
+  cotaId: Hex,
+  cotaInfo: CotaInfo,
+  fee = FEE,
+  isMainnet = false,
+) => {
+  const cotaType = getCotaTypeScript(isMainnet)
+  const cotaCells = await service.collector.getCells(cotaLock, cotaType)
+  if (!cotaCells || cotaCells.length === 0) {
+    throw new Error("Cota cell doesn't exist")
+  }
+
+  const cotaCell = cotaCells[0]
+  const inputs = [
+    {
+      previousOutput: cotaCell.outPoint,
+      since: '0x0',
+    },
+  ]
+
+  const outputs = [cotaCell.output]
+  outputs[0].capacity = `0x${(BigInt(outputs[0].capacity) - fee).toString(16)}`
+
+  const cotaOutput = await service.collector.getLiveCell(cotaCell.outPoint)
+  const outputsData = [cotaOutput.data?.content]
+
+  const cellDeps = [getCotaCellDep(isMainnet)]
+
+  const rawTx: any = {
+    version: '0x0',
+    cellDeps,
+    headerDeps: [],
+    inputs,
+    outputs,
+    outputsData,
+    witnesses: [],
+  }
+  rawTx.witnesses = rawTx.inputs.map((_, i) =>
+    i > 0 ? '0x' : { lock: '', inputType: '', outputType: generateCotaMetadata(cotaInfo, cotaId) },
+  )
+  return rawTx
+}
diff --git a/src/service/cota/extension.ts b/src/service/cota/extension.ts
new file mode 100644
index 0000000..40638fc
--- /dev/null
+++ b/src/service/cota/extension.ts
@@ -0,0 +1,76 @@
+import { serializeScript } from '@nervosnetwork/ckb-sdk-utils'
+import { Service } from '../..'
+import { FEE, getCotaTypeScript, getCotaCellDep } from '../../constants'
+import { ExtensionReq } from '../../types'
+
+
+enum Action {
+  Add,
+  Update
+}
+
+const generateExtensionTx = async (
+  service: Service,
+  cotaLock: CKBComponents.Script,
+  fee = FEE,
+  isMainnet = false,
+  action: Action,
+) => {
+  const cotaType = getCotaTypeScript(isMainnet)
+  const cotaCells = await service.collector.getCells(cotaLock, cotaType)
+  if (!cotaCells || cotaCells.length === 0) {
+    throw new Error("Cota cell doesn't exist")
+  }
+  const cotaCell = cotaCells[0]
+  const inputs = [
+    {
+      previousOutput: cotaCell.outPoint,
+      since: '0x0',
+    },
+  ]
+
+  const outputs = [cotaCell.output]
+  outputs[0].capacity = `0x${(BigInt(outputs[0].capacity) - fee).toString(16)}`
+
+  const extensionReq: ExtensionReq = {
+    lockScript: serializeScript(cotaLock),
+  }
+
+  const { smtRootHash, extensionSmtEntry } = await service.aggregator.generateExtensionSmt(extensionReq)
+  const cotaCellData = `0x02${smtRootHash}`
+
+  const outputsData = [cotaCellData]
+  const cellDeps = [getCotaCellDep(isMainnet)]
+
+  const rawTx = {
+    version: '0x0',
+    cellDeps,
+    headerDeps: [],
+    inputs,
+    outputs,
+    outputsData,
+    witnesses: [],
+  } as any
+
+  const prefix = action == Action.Add ? '0xF0' : '0xF1'
+  rawTx.witnesses = rawTx.inputs.map((_, i) =>
+    i > 0 ? '0x' : { lock: '', inputType: `${prefix}${extensionSmtEntry}`, outputType: '' },
+  )
+  return rawTx
+}
+
+
+export const generateAddExtensionTx = async (
+  service: Service,
+  cotaLock: CKBComponents.Script,
+  fee = FEE,
+  isMainnet = false
+) => await generateExtensionTx(service, cotaLock, fee, isMainnet, Action.Add)
+
+
+  export const generateUpdateExtensionTx = async (
+  service: Service,
+  cotaLock: CKBComponents.Script,
+  fee = FEE,
+  isMainnet = false
+) => await generateExtensionTx(service, cotaLock, fee, isMainnet, Action.Update)
\ No newline at end of file
diff --git a/src/service/cota/transfer-update.ts b/src/service/cota/transfer-update.ts
index 355037d..e759bb5 100644
--- a/src/service/cota/transfer-update.ts
+++ b/src/service/cota/transfer-update.ts
@@ -35,9 +35,8 @@ export const generateTransferUpdateCotaTx = async (
     transferOutPoint: append0x(serializeOutPoint(cotaCell.outPoint).slice(26)),
     transfers,
   }
-  const { smtRootHash, transferUpdateSmtEntry, withdrawBlockHash } = await service.aggregator.generateTransferUpdateCotaSmt(
-    transferUpdateReq,
-  )
+  const { smtRootHash, transferUpdateSmtEntry, withdrawBlockHash } =
+    await service.aggregator.generateTransferUpdateCotaSmt(transferUpdateReq)
   const outputsData = [`0x02${smtRootHash}`]
 
   const cellDeps = [getCotaCellDep(isMainnet)]
diff --git a/src/service/cota/transfer.ts b/src/service/cota/transfer.ts
index b923d77..670eb08 100644
--- a/src/service/cota/transfer.ts
+++ b/src/service/cota/transfer.ts
@@ -35,12 +35,14 @@ export const generateTransferCotaTx = async (
     transferOutPoint: append0x(serializeOutPoint(cotaCell.outPoint).slice(26)),
     transfers,
   }
-  const { smtRootHash, transferSmtEntry, withdrawBlockHash } = await service.aggregator.generateTransferCotaSmt(transferReq)
+  const { smtRootHash, transferSmtEntry, withdrawBlockHash } = await service.aggregator.generateTransferCotaSmt(
+    transferReq,
+  )
   const outputsData = [`0x02${smtRootHash}`]
 
   const cellDeps = [getCotaCellDep(isMainnet)]
   const headerDeps = [`0x${withdrawBlockHash}`]
-  
+
   const rawTx = {
     version: '0x0',
     cellDeps,
diff --git a/src/service/registry/index.ts b/src/service/registry/index.ts
index 1cf45cc..a2110f9 100644
--- a/src/service/registry/index.ts
+++ b/src/service/registry/index.ts
@@ -75,7 +75,9 @@ export const generateRegisterCotaTx = async (
   outputs[length - 1].capacity = `0x${(BigInt(outputs[length - 1].capacity) - fee).toString(16)}`
 
   const lockHashes = cotaLocks.map(lock => scriptToHash(lock))
-  const { smtRootHash, registrySmtEntry, outputAccountNum } = await service.aggregator.generateRegisterCotaSmt(lockHashes)
+  const { smtRootHash, registrySmtEntry, outputAccountNum } = await service.aggregator.generateRegisterCotaSmt(
+    lockHashes,
+  )
   const registryCellData = `0x01${smtRootHash}${u64ToBe(BigInt(outputAccountNum))}`
 
   const outputsData = outputs.map((_, i) => (i === 0 ? registryCellData : i !== outputs.length - 1 ? '0x02' : '0x'))
@@ -97,7 +99,6 @@ export const generateRegisterCotaTx = async (
   return rawTx
 }
 
-
 export const generateUpdateCcidsTx = async (
   service: Service,
   fee = FEE,
diff --git a/src/types/request.ts b/src/types/request.ts
index 371d47b..c63e65d 100644
--- a/src/types/request.ts
+++ b/src/types/request.ts
@@ -118,3 +118,7 @@ export interface GetCotaCountReq extends SmtReq {
   lockScript: Bytes
   cotaId: Byte20
 }
+
+export interface ExtensionReq extends SmtReq {
+  lockScript: Bytes
+}
diff --git a/src/types/response.ts b/src/types/response.ts
index cd2992e..e35fa95 100644
--- a/src/types/response.ts
+++ b/src/types/response.ts
@@ -146,3 +146,9 @@ export interface GetCotaCountResp {
   count: number
   blockNumber: bigint
 }
+
+export interface ExtensionResp extends SmtResp {
+  smtRootHash: Byte32
+  extensionSmtEntry: Bytes
+  blockNumber: bigint
+}