diff --git a/Storage/Storage/LCObject.cs b/Storage/Storage/LCObject.cs
index cdbd90f..67bc2dd 100644
--- a/Storage/Storage/LCObject.cs
+++ b/Storage/Storage/LCObject.cs
@@ -125,7 +125,8 @@ namespace LeanCloud.Storage {
                 if (key.StartsWith("_")) {
                     throw new ArgumentException("key should not start with '_'");
                 }
-                if (key == "objectId" || key == "createdAt" || key == "updatedAt") {
+                if (key == "objectId" || key == "createdAt" || key == "updatedAt" ||
+                    key == "className" || key == "ACL") {
                     throw new ArgumentException($"{key} is reserved by LeanCloud");
                 }
                 LCSetOperation setOp = new LCSetOperation(value);