diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index d7bfc42e2..23f2610cc 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -501,7 +501,7 @@ func (bc *Blockchain) storeBlock(block *block.Block) error {
 			}
 			oldSpentCoinLen := len(spentCoin.Items)
 			for _, input := range inputs {
-				unspent.States[input.PrevIndex] = state.CoinSpent
+				unspent.States[input.PrevIndex] |= state.CoinSpent
 				prevTXOutput := prevTX.Outputs[input.PrevIndex]
 				account, err := cache.GetAccountStateOrNew(prevTXOutput.ScriptHash)
 				if err != nil {
diff --git a/pkg/core/dao.go b/pkg/core/dao.go
index fbab4c6ef..f211a2d42 100644
--- a/pkg/core/dao.go
+++ b/pkg/core/dao.go
@@ -590,7 +590,7 @@ func (dao *dao) IsDoubleSpend(tx *transaction.Transaction) bool {
 			return false
 		}
 		for _, input := range inputs {
-			if int(input.PrevIndex) >= len(unspent.States) || unspent.States[input.PrevIndex] == state.CoinSpent {
+			if int(input.PrevIndex) >= len(unspent.States) || (unspent.States[input.PrevIndex]&state.CoinSpent) != 0 {
 				return true
 			}
 		}