diff --git a/src/Qiniu/Processing/Operation.php b/src/Qiniu/Processing/Operation.php
index c5853205..203499ef 100644
--- a/src/Qiniu/Processing/Operation.php
+++ b/src/Qiniu/Processing/Operation.php
@@ -38,7 +38,7 @@ public function execute($key, $fops)
         if (!$resp->ok()) {
             return array(null, new Error($url, $resp));
         }
-        if ($resp->json() != null) {
+        if ($resp->json() !== null) {
             return array($resp->json(), null);
         }
         return array($resp->body, null);