diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index e8dddb1238708863422a90166c42eba4fe18f02d..d8017a8727af05c947323f424c41abc642b91d6d 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -558,15 +558,6 @@ static void doSetOneRowPtr(SReqResultInfo* pResultInfo) {
 
         pResultInfo->length[i] = varDataLen(pStart);
         pResultInfo->row[i] = varDataVal(pStart);
-
-        if (type == TSDB_DATA_TYPE_NCHAR) {
-          int32_t len = taosUcs4ToMbs((TdUcs4*)varDataVal(pStart), varDataLen(pStart), varDataVal(pResultInfo->convertBuf[i]));
-          ASSERT(len <= bytes);
-
-          pResultInfo->row[i] = varDataVal(pResultInfo->convertBuf[i]);
-          varDataSetLen(pResultInfo->convertBuf[i], len);
-          pResultInfo->length[i] = len;
-        }
       } else {
         pResultInfo->row[i] = NULL;
       }
@@ -689,12 +680,6 @@ static int32_t doPrepareResPtr(SReqResultInfo* pResInfo) {
     if (pResInfo->row == NULL || pResInfo->pCol == NULL || pResInfo->length == NULL || pResInfo->convertBuf == NULL) {
       return TSDB_CODE_OUT_OF_MEMORY;
     }
-
-    for(int32_t i = 0; i < pResInfo->numOfCols; ++i) {
-      if(pResInfo->fields[i].type == TSDB_DATA_TYPE_NCHAR) {
-        pResInfo->convertBuf[i] = taosMemoryCalloc(1, NCHAR_WIDTH_TO_BYTES(pResInfo->fields[i].bytes));
-      }
-    }
   }
 
   return TSDB_CODE_SUCCESS;
@@ -731,6 +716,35 @@ int32_t setResultDataPtr(SReqResultInfo* pResultInfo, TAOS_FIELD* pFields, int32
     pStart += colLength[i];
   }
 
+  for (int32_t i = 0; i < numOfCols; ++i) {
+    int32_t type = pResultInfo->fields[i].type;
+    int32_t bytes = pResultInfo->fields[i].bytes;
+
+    if (type == TSDB_DATA_TYPE_NCHAR) {
+      char* p = taosMemoryRealloc(pResultInfo->convertBuf[i], colLength[i]);
+      if (p == NULL) {
+        return TSDB_CODE_OUT_OF_MEMORY;
+      }
+      pResultInfo->convertBuf[i] = p;
+
+      SResultColumn* pCol = &pResultInfo->pCol[i];
+      for (int32_t j = 0; j < numOfRows; ++j) {
+        if (pCol->offset[j] != -1) {
+          pStart = pCol->offset[j] + pCol->pData;
+
+          int32_t len = taosUcs4ToMbs((TdUcs4*)varDataVal(pStart), varDataLen(pStart), varDataVal(p));
+          ASSERT(len <= bytes);
+
+          varDataSetLen(p, len);
+          pCol->offset[j] = (p - pResultInfo->convertBuf[i]);
+          p += (len + VARSTR_HEADER_SIZE);
+        }
+      }
+
+      pResultInfo->pCol[i].pData = pResultInfo->convertBuf[i];
+    }
+  }
+
   return TSDB_CODE_SUCCESS;
 }