diff --git a/src/vnode/tsdb/src/tsdbMain.c b/src/vnode/tsdb/src/tsdbMain.c
index d18e766c38960b07669f6a66daac408e524c770a..984f2ca203c27d17b59e5ee495446c31999dfc60 100644
--- a/src/vnode/tsdb/src/tsdbMain.c
+++ b/src/vnode/tsdb/src/tsdbMain.c
@@ -1069,10 +1069,12 @@ static int tsdbWriteBlockToFileImpl(SFile *pFile, SDataCols *pCols, int pointsTo
 
   // Write the block
   if (write(pFile->fd, (void *)pCompData, size) < 0) goto _err;
+  *len += size;
   for (int iCol = 0; iCol < pCols->numOfCols; iCol++) {
     SDataCol *pDataCol = pCols->cols + iCol;
     SCompCol *pCompCol = pCompData->cols + iCol;
     if (write(pFile->fd, pDataCol->pData, pCompCol->len) < 0) goto _err;
+    *len += pCompCol->len;
   }
 
   if (pCompData == NULL) free((void *)pCompData);
@@ -1083,22 +1085,46 @@ _err:
   return -1;
 }
 
-static int tsdbWriteBlockToFile(STsdbRepo *pRepo, SCompIdx *pIdx, SCompInfo *pCompInfo, SDataCols *pCols, SCompBlock *pCompBlock) {
-  STsdbCfg *pCfg = &(pRepo->config);
+static int compareKeyBlock(const void *arg1, const void *arg2) {
+  TSKEY key = *(TSKEY *)arg1;
+  SCompBlock *pBlock = (SCompBlock *)arg2;
+
+  if (key < pBlock->keyFirst) {
+    return -1;
+  } else if (key > pBlock->keyLast) {
+    return 1;
+  }
+
+  return 0;
+}
+
+static int tsdbWriteBlockToFile(STsdbRepo *pRepo, SFileGroup *pGroup, SCompIdx *pIdx, SCompInfo *pCompInfo, SDataCols *pCols, SCompBlock *pCompBlock, SFile *lFile, int64_t uid) {
+  STsdbCfg * pCfg = &(pRepo->config);
   SCompData *pCompData = NULL;
+  SFile *    pFile = NULL;
+  int        numOfPointsToWrite = 0;
+  int64_t    offset = 0;
+  int32_t    len = 0;
 
   memset((void *)pCompBlock, 0, sizeof(SCompBlock));
 
   if (pCompInfo == NULL) {
-    if (pCols->numOfPoints > pCfg->minRowsPerFileBlock) { // Write to .data file
-      // tsdbWriteBlockToFileImpl()
-    } else { // Write to .last or .l file
+    // Just append the data block to .data or .l or .last file
+    numOfPointsToWrite = pCols->numOfPoints;
+    if (pCols->numOfPoints > pCfg->minRowsPerFileBlock) {  // Write to .data file
+      pFile = &(pGroup->files[TSDB_FILE_TYPE_DATA]);
+    } else {  // Write to .last or .l file
       pCompBlock->last = 1;
-
+      if (lFile) {
+        pFile = lFile;
+      } else {
+        pFile = &(pGroup->files[TSDB_FILE_TYPE_LAST]);
+      }
     }
-    // pCompBlock->offset = ;
-    // pCompBlock->len = ;
-    pCompBlock->algorithm = 2; // TODO : add to configuration
+    tsdbWriteBlockToFileImpl(pFile, pCols, numOfPointsToWrite, &offset, &len, uid);
+    pCompBlock->offset = offset;
+    pCompBlock->len = len;
+    pCompBlock->algorithm = 2;  // TODO : add to configuration
     pCompBlock->sversion = pCols->sversion;
     pCompBlock->numOfPoints = pCols->numOfPoints;
     pCompBlock->numOfSubBlocks = 1;
@@ -1106,7 +1132,38 @@ static int tsdbWriteBlockToFile(STsdbRepo *pRepo, SCompIdx *pIdx, SCompInfo *pCo
     pCompBlock->keyFirst = dataColsKeyFirst(pCols);
     pCompBlock->keyLast = dataColsKeyLast(pCols);
   } else {
-    // Need to merge
+    // Need to merge the block to either the last block or the other block
+    TSKEY       keyFirst = dataColsKeyFirst(pCols);
+    SCompBlock *pMergeBlock = NULL;
+
+    // Search the block to merge in
+    void *ptr = taosbsearch((void *)&keyFirst, (void *)(pCompInfo->blocks), sizeof(SCompBlock), pIdx->numOfSuperBlocks,
+                            compareKeyBlock, TD_GE);
+    if (ptr == NULL) {
+      // No block greater or equal than the key, but there are data in the .last file, need to merge the last file block
+      // and merge the data
+      pMergeBlock = TSDB_COMPBLOCK_AT(pCompInfo, pIdx->numOfSuperBlocks - 1);
+    } else {
+      pMergeBlock = (SCompBlock *)ptr;
+    }
+
+    if (pMergeBlock->last) {
+      if (pMergeBlock->last + pCols->numOfPoints > pCfg->minRowsPerFileBlock) {
+        // Need to load the data from .last and combine data in pCols to write to .data file
+
+      } else { // Just append the block to .last or .l file
+        if (lFile) {
+          // read the block from .last file and merge with pCols, write to .l file
+
+        } else {
+          // tsdbWriteBlockToFileImpl();
+        }
+      }
+    } else { // The block need to merge in .data file
+
+    }
+
   }
-  return 0;
+
+  return numOfPointsToWrite;
 }
\ No newline at end of file