diff --git a/frameworks/native/backup_ext/src/ext_extension.cpp b/frameworks/native/backup_ext/src/ext_extension.cpp
index 616cb5fcfb18788a3b581d18c975053d68d47b14..a45e61d8aef2745bbc8789ebd76164a879efb699 100644
--- a/frameworks/native/backup_ext/src/ext_extension.cpp
+++ b/frameworks/native/backup_ext/src/ext_extension.cpp
@@ -1004,7 +1004,7 @@ void BackupExtExtension::AsyncTaskBackup(const string config)
             if (!ptr->StopExtTimer()) {
                 throw BError(BError::Codes::EXT_TIMER_ERROR, "Failed to stop extTimer");
             }
-            int64_t totalSize;
+            int64_t totalSize = 0;
             TarMap bigFileInfo;
             map<string, size_t> smallFiles;
             BJsonCachedEntity<BJsonEntityExtensionConfig> cachedEntity(config);