diff --git a/src/neo/Ledger/Blockchain.cs b/src/neo/Ledger/Blockchain.cs
index fd76d1ebca..0a535f9a5b 100644
--- a/src/neo/Ledger/Blockchain.cs
+++ b/src/neo/Ledger/Blockchain.cs
@@ -331,6 +331,7 @@ private VerifyResult OnNewBlock(Block block)
                 if (!block.Hash.Equals(header_index[(int)block.Index]))
                     return VerifyResult.Invalid;
             }
+            block_cache.TryAdd(block.Hash, block);
             if (block.Index == Height + 1)
             {
                 Block block_persist = block;
@@ -370,7 +371,6 @@ private VerifyResult OnNewBlock(Block block)
             }
             else
             {
-                block_cache.Add(block.Hash, block);
                 if (block.Index + 100 >= header_index.Count)
                     system.LocalNode.Tell(new LocalNode.RelayDirectly { Inventory = block });
                 if (block.Index == header_index.Count)
@@ -430,7 +430,7 @@ private VerifyResult OnNewTransaction(Transaction transaction)
 
         private void OnPersistCompleted(Block block)
         {
-            block_cache.Remove(block.Hash);
+            block_cache.Remove(block.PrevHash);
             MemPool.UpdatePoolForBlockPersisted(block, currentSnapshot);
             Context.System.EventStream.Publish(new PersistCompleted { Block = block });
         }