diff --git a/src/gausskernel/storage/access/ustore/undo/knl_uundotxn.cpp b/src/gausskernel/storage/access/ustore/undo/knl_uundotxn.cpp
index 82c886d0e..9e22de84d 100644
--- a/src/gausskernel/storage/access/ustore/undo/knl_uundotxn.cpp
+++ b/src/gausskernel/storage/access/ustore/undo/knl_uundotxn.cpp
@@ -321,9 +321,9 @@ UndoSlotPtr GetNextSlotPtr(UndoSlotPtr slotPtr)
     UndoSlotOffset blkOffset = slotOffset % BLCKSZ;
     UndoSlotOffset offset = blkOffset + MAXALIGN(sizeof(undo::TransactionSlot));
     if (BLCKSZ - offset < MAXALIGN(sizeof(undo::TransactionSlot))) {
-        offset = (block + 1) * BLCKSZ + UNDO_LOG_BLOCK_HEADER_SIZE;
+        offset = (UndoSlotOffset)(block + 1) * BLCKSZ + UNDO_LOG_BLOCK_HEADER_SIZE;
     } else {
-        offset += block * BLCKSZ;
+        offset += (UndoSlotOffset)block * BLCKSZ;
     }
     Assert (offset <= UNDO_LOG_MAX_SIZE);
     return MAKE_UNDO_PTR(UNDO_PTR_GET_ZONE_ID(slotPtr), offset);