diff --git a/core/ledger/validator.go b/core/ledger/validator.go
index 42d5b7686..e18c6f53c 100644
--- a/core/ledger/validator.go
+++ b/core/ledger/validator.go
@@ -54,13 +54,13 @@ func TransactionCheck(block *Block) error {
 		if errCode := tx.VerifyTransaction(txn); errCode != ErrNoError {
 			return errors.New("transaction sanity check failed")
 		}
-		if errCode := tx.VerifyTransactionWithBlock(TransactionArray(block.Transactions)); errCode != ErrNoError {
-			return errors.New("transaction block check failed")
-		}
 		if errCode := tx.VerifyTransactionWithLedger(txn); errCode != ErrNoError {
 			return errors.New("transaction history check failed")
 		}
 	}
+	if errCode := tx.VerifyTransactionWithBlock(TransactionArray(block.Transactions)); errCode != ErrNoError {
+		return errors.New("transaction block check failed")
+	}
 
 	return nil
 }
diff --git a/core/transaction/pool/pool.go b/core/transaction/pool/pool.go
index fb84138d3..8ae74ad0a 100644
--- a/core/transaction/pool/pool.go
+++ b/core/transaction/pool/pool.go
@@ -51,10 +51,6 @@ func (tp *TxnPool) AppendTxnPool(txn *Transaction) ErrCode {
 		log.Info("Transaction verification failed", txn.Hash())
 		return errCode
 	}
-	if errCode := VerifyTransactionWithBlock(TransactionMap(tp.txnList)); errCode != ErrNoError {
-		log.Info("Transaction verification with block failed", txn.Hash())
-		return errCode
-	}
 	if errCode := VerifyTransactionWithLedger(txn); errCode != ErrNoError {
 		log.Info("Transaction verification with ledger failed", txn.Hash())
 		return errCode
@@ -72,7 +68,16 @@ func (tp *TxnPool) AppendTxnPool(txn *Transaction) ErrCode {
 	}
 
 	//add the transaction to process scope
-	tp.addtxnList(txn)
+	if tp.addtxnList(txn) {
+		// Check duplicate UTXO reference after append successful
+		if errCode := VerifyTransactionWithBlock(TransactionMap(tp.txnList)); errCode != ErrNoError {
+			log.Info("Transaction verification with block failed", txn.Hash())
+			tp.deltxnList(txn) // Revert previous append action
+			return errCode
+		}
+	} else {
+		return ErrDuplicatedTx // Don't broadcast this txn if hash duplicated
+	}
 
 	return ErrNoError
 }
diff --git a/core/transaction/validator.go b/core/transaction/validator.go
index 74a38db51..8a7bb2ca6 100644
--- a/core/transaction/validator.go
+++ b/core/transaction/validator.go
@@ -180,15 +180,13 @@ func VerifyTransactionWithLedger(Tx *Transaction) ErrCode {
 
 //validate the transaction of duplicate UTXO input
 func CheckDuplicateInput(tx *Transaction) error {
-	if len(tx.Inputs) == 0 {
-		return nil
-	}
-	for i, utxoin := range tx.Inputs {
-		for j := 0; j < i; j++ {
-			if utxoin.ReferTxID == tx.Inputs[j].ReferTxID && utxoin.ReferTxOutputIndex == tx.Inputs[j].ReferTxOutputIndex {
-				return errors.New("invalid transaction")
-			}
+	dupMap := make(map[string]struct{})
+	for _, utxoin := range tx.Inputs {
+		k := utxoin.ToString()
+		if _, ok := dupMap[k]; ok { // ok means duplicate
+			return errors.New("invalid transaction")
 		}
+		dupMap[k] = struct{}{}
 	}
 	return nil
 }
diff --git a/db/store.go b/db/store.go
index aa32f635a..d9432fadf 100644
--- a/db/store.go
+++ b/db/store.go
@@ -251,11 +251,7 @@ func (cs *ChainStore) InitLedgerStoreWithGenesisBlock(genesisBlock *Block) (uint
 func (cs *ChainStore) IsTxHashDuplicate(txhash Uint256) bool {
 	prefix := []byte{byte(DATA_Transaction)}
 	_, err_get := cs.st.Get(append(prefix, txhash.ToArray()...))
-	if err_get != nil {
-		return false
-	} else {
-		return true
-	}
+	return err_get == nil
 }
 
 func (cs *ChainStore) IsDoubleSpend(tx *tx.Transaction) bool {