diff --git a/QiniuSDK/QiniuUtils.m b/QiniuSDK/QiniuUtils.m
index 09f5b4f..b175140 100644
--- a/QiniuSDK/QiniuUtils.m
+++ b/QiniuSDK/QiniuUtils.m
@@ -16,7 +16,7 @@
 
 NSError *qiniuErrorWithOperation(AFHTTPRequestOperation *operation, NSError *error) {
     
-    if (operation == nil) {
+    if (operation == nil || operation.responseObject == nil) {
         return error;
     }