diff --git a/source/common/src/tvariant.c b/source/common/src/tvariant.c
index a01c393441..830a6199d8 100644
--- a/source/common/src/tvariant.c
+++ b/source/common/src/tvariant.c
@@ -366,6 +366,7 @@ static int32_t toBinary(SVariant *pVariant, char **pDest, int32_t *pDestSize) {
   }
 
   if (pBuf != NULL) {
+    taosMemoryFree(pVariant->pz);
     *pDest = pBuf;
   }