diff --git a/Storage/Storage.Test/BaseTest.cs b/Storage/Storage.Test/BaseTest.cs
index cd2a0e6..310e71d 100644
--- a/Storage/Storage.Test/BaseTest.cs
+++ b/Storage/Storage.Test/BaseTest.cs
@@ -43,6 +43,24 @@ namespace Storage.Test {
         internal Account() : base("Account") { }
     }
 
+    internal class ObjectWithFile : LCObject {
+        internal LCFile File {
+            get => this["file"] as LCFile;
+            set {
+                this["file"] = value;
+            }
+        }
+
+        internal LCUser Owner {
+            get => this["owner"] as LCUser;
+            set {
+                this["owner"] = value;
+            }
+        }
+
+        internal ObjectWithFile() : base("ObjectWithFile") {}
+    }
+
     public class BaseTest {
         internal const string AppId = "ikGGdRE2YcVOemAaRbgp1xGJ-gzGzoHsz";
         internal const string AppKey = "NUKmuRbdAhg1vrb2wexYo1jo";
@@ -59,6 +77,7 @@ namespace Storage.Test {
             LCObject.RegisterSubclass("Account", () => new Account());
             LCObject.RegisterSubclass("Hello", () => new Hello());
             LCObject.RegisterSubclass("World", () => new World());
+            LCObject.RegisterSubclass("ObjectWithFile", () => new ObjectWithFile());
         }
 
         [TearDown]
diff --git a/Storage/Storage.Test/SubClassTest.cs b/Storage/Storage.Test/SubClassTest.cs
index 6a48082..6cd73cf 100644
--- a/Storage/Storage.Test/SubClassTest.cs
+++ b/Storage/Storage.Test/SubClassTest.cs
@@ -34,5 +34,24 @@ namespace Storage.Test {
             await account.Save();
             await account.Delete();
         }
+
+        [Test]
+        public async Task ObjectWithFile() {
+            LCUser user = await LCUser.Login("hello", "world");
+            ObjectWithFile obj = new ObjectWithFile() {
+                File = new LCFile("avatar", "../../../../../assets/hello.png"),
+                Owner = user
+            };
+            await obj.Save();
+
+            LCQuery<ObjectWithFile> query = new LCQuery<ObjectWithFile>("ObjectWithFile");
+            ObjectWithFile obj2 = await query.Get(obj.ObjectId);
+
+            TestContext.WriteLine(obj2.File.Url);
+            TestContext.WriteLine(obj2.Owner.ObjectId);
+
+            Assert.IsNotNull(obj2.File.Url);
+            Assert.IsNotNull(obj2.Owner.ObjectId);
+        }
     }
 }
diff --git a/Storage/Storage/Internal/Codec/LCDecoder.cs b/Storage/Storage/Internal/Codec/LCDecoder.cs
index ec351ee..79402f8 100644
--- a/Storage/Storage/Internal/Codec/LCDecoder.cs
+++ b/Storage/Storage/Internal/Codec/LCDecoder.cs
@@ -13,14 +13,16 @@ namespace LeanCloud.Storage.Internal.Codec {
                         return DecodeDate(dict);
                     } else if (type == "Bytes") {
                         return DecodeBytes(dict);
-                    } else if (type == "Object") {
+                    } else if (type == "Pointer") {
                         return DecodeObject(dict);
-                    } else if (type == "Pointer" || type == "Object") {
+                    } else if (type == "Object") {
                         return DecodeObject(dict);
                     } else if (type == "Relation") {
                         return DecodeRelation(dict);
                     } else if (type == "GeoPoint") {
                         return DecodeGeoPoint(dict);
+                    } else if (type == "File") {
+                        return DecodeFile(dict);
                     }
                 }
                 Dictionary<string, object> d = new Dictionary<string, object>();
@@ -61,6 +63,13 @@ namespace LeanCloud.Storage.Internal.Codec {
             return obj;
         }
 
+        public static LCFile DecodeFile(IDictionary dict) {
+            LCFile file = new LCFile();
+            LCObjectData objectData = LCObjectData.Decode(dict as Dictionary<string, object>);
+            file.Merge(objectData);
+            return file;
+        }
+
         public static LCRelation<LCObject> DecodeRelation(IDictionary dict) {
             LCRelation<LCObject> relation = new LCRelation<LCObject>();
             relation.TargetClass = dict["className"].ToString();
diff --git a/Storage/Storage/Public/LCObject.cs b/Storage/Storage/Public/LCObject.cs
index 62868ea..273163e 100644
--- a/Storage/Storage/Public/LCObject.cs
+++ b/Storage/Storage/Public/LCObject.cs
@@ -73,12 +73,8 @@ namespace LeanCloud.Storage {
             }
         }
 
-        bool isNew;
-
         bool IsDirty {
-            get {
-                return isNew || estimatedData.Count > 0;
-            }
+            get; set;
         }
 
         /// <summary>
@@ -96,7 +92,7 @@ namespace LeanCloud.Storage {
             operationDict = new Dictionary<string, ILCOperation>();
 
             data.ClassName = className;
-            isNew = true;
+            IsDirty = true;
         }
 
         /// <summary>
@@ -111,7 +107,7 @@ namespace LeanCloud.Storage {
             }
             LCObject obj = Create(className);
             obj.data.ObjectId = objectId;
-            obj.isNew = false;
+            obj.IsDirty = false;
             return obj;
         }
 
@@ -327,8 +323,19 @@ namespace LeanCloud.Storage {
         static async Task SaveBatches(Stack<LCBatch> batches) {
             while (batches.Count > 0) {
                 LCBatch batch = batches.Pop();
+
+                // 特殊处理 File 依赖
+                IEnumerable<LCFile> dirtyFiles = batch.objects.Where(item => (item is LCFile) && item.IsDirty)
+                                                        .Cast<LCFile>();
+                foreach (LCFile file in dirtyFiles) {
+                    await file.Save();
+                }
+
                 List<LCObject> dirtyObjects = batch.objects.Where(item => item.IsDirty)
                                                             .ToList();
+                if (dirtyObjects.Count == 0) {
+                    continue;
+                }
 
                 List<Dictionary<string, object>> requestList = dirtyObjects.Select(item => {
                     string path = item.ObjectId == null ?
@@ -567,6 +574,7 @@ namespace LeanCloud.Storage {
             } else {
                 operationDict[key] = op;
             }
+            IsDirty = true;
         }
 
         public void Merge(LCObjectData objectData) {
@@ -587,7 +595,7 @@ namespace LeanCloud.Storage {
             RebuildEstimatedData();
             // 清空操作
             operationDict.Clear();
-            isNew = false;
+            IsDirty = false;
         }
 
         void RebuildEstimatedData() {