diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 51968eee4568b1695e5cd1382339d9b32ff8c7b3..a4d929e682b840c8c7625d5fd7278e9ad31bcd20 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -1654,7 +1654,9 @@ static int32_t loadFileDataBlock(STsdbQueryHandle* pQueryHandle, SBlock* pBlock,
 
   if (asc) {
     // query ended in/started from current block
-    if (pQueryHandle->window.ekey < pBlock->keyLast || pCheckInfo->lastKey > pBlock->keyFirst) {
+    if ((pQueryHandle->window.ekey < pBlock->keyLast || pCheckInfo->lastKey > pBlock->keyFirst )
+         && pCheckInfo->lastKey <= pBlock->keyLast) {
+      // if mem lastKey > block lastKey , should deal with handleDatamergeIfNeed
       if ((code = doLoadFileDataBlock(pQueryHandle, pBlock, pCheckInfo, cur->slot)) != TSDB_CODE_SUCCESS) {
         *exists = false;
         return code;
@@ -1670,10 +1672,9 @@ static int32_t loadFileDataBlock(STsdbQueryHandle* pQueryHandle, SBlock* pBlock,
         cur->pos = 0;
       }
 
-      assert(pCheckInfo->lastKey <= pBlock->keyLast);
       doMergeTwoLevelData(pQueryHandle, pCheckInfo, pBlock);
     } else {  // the whole block is loaded in to buffer
-      cur->pos = asc? 0:(pBlock->numOfRows - 1);
+      cur->pos = 0;
       code = handleDataMergeIfNeeded(pQueryHandle, pBlock, pCheckInfo);
     }
   } else {  //desc order, query ended in current block
@@ -1693,7 +1694,7 @@ static int32_t loadFileDataBlock(STsdbQueryHandle* pQueryHandle, SBlock* pBlock,
       assert(pCheckInfo->lastKey >= pBlock->keyFirst);
       doMergeTwoLevelData(pQueryHandle, pCheckInfo, pBlock);
     } else {
-      cur->pos = asc? 0:(pBlock->numOfRows-1);
+      cur->pos = pBlock->numOfRows - 1;
       code = handleDataMergeIfNeeded(pQueryHandle, pBlock, pCheckInfo);
     }
   }