diff --git a/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs b/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
index 1538ff0..dd3af7e 100644
--- a/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
+++ b/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
@@ -1899,15 +1899,11 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
         sb.AppendLine($"    internal static readonly {ci.ClassName}_GeneratedReader Instance = new();");
         sb.AppendLine();
 
-        // ReadObject — IGeneratedBinaryReader implementation
-        sb.AppendLine("    public object? ReadObject<TInput>(AcBinaryDeserializer.BinaryDeserializationContext<TInput> context, int depth, int cacheIndex)");
+        // ReadProperties — reads all properties into an existing instance (mirrors WriteProperties)
+        sb.AppendLine("    public void ReadProperties<TInput>(object value, AcBinaryDeserializer.BinaryDeserializationContext<TInput> context, int depth)");
         sb.AppendLine("        where TInput : struct, IBinaryInputBase");
         sb.AppendLine("    {");
-        sb.AppendLine($"        var obj = new {ci.FullTypeName}();");
-        sb.AppendLine();
-        sb.AppendLine("        if (cacheIndex >= 0)");
-        sb.AppendLine("            context.RegisterInternedValueAt(cacheIndex, obj);");
-        sb.AppendLine();
+        sb.AppendLine($"        var obj = Unsafe.As<{ci.FullTypeName}>(value);");
 
         // Emit property reads — markerless for primitive types, markered for the rest
         foreach (var p in ci.Properties)
@@ -1916,7 +1912,17 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             EmitReadProp(sb, p, "        ", ci.EnableMetadata);
         }
 
+        sb.AppendLine("    }");
         sb.AppendLine();
+
+        // ReadObject — IGeneratedBinaryReader implementation (delegates to ReadProperties)
+        sb.AppendLine("    public object? ReadObject<TInput>(AcBinaryDeserializer.BinaryDeserializationContext<TInput> context, int depth, int cacheIndex)");
+        sb.AppendLine("        where TInput : struct, IBinaryInputBase");
+        sb.AppendLine("    {");
+        sb.AppendLine($"        var obj = new {ci.FullTypeName}();");
+        sb.AppendLine("        if (cacheIndex >= 0)");
+        sb.AppendLine("            context.RegisterInternedValueAt(cacheIndex, obj);");
+        sb.AppendLine("        ReadProperties<TInput>(obj, context, depth);");
         sb.AppendLine("        return obj;");
         sb.AppendLine("    }");
         sb.AppendLine("}");
@@ -2103,24 +2109,45 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
         if (!p.ChildNeedsRefScan)
         {
             // Compile-time proven: child never tracked → only Object (+ Null for nullable) in stream
+            // Inline: parent creates instance, calls ReadProperties directly (mirrors EmitDirectObjectWrite)
             if (p.IsNullable)
             {
                 sb.AppendLine($"{i}if ({tc} == BinaryTypeCode.Null) {{ /* null */ }}");
-                sb.AppendLine($"{i}else {a} = {cast}{reader}.Instance.ReadObject(context, {nd}, -1)!;");
+                sb.AppendLine($"{i}else");
+                sb.AppendLine($"{i}{{");
+                sb.AppendLine($"{i}    var rc_{p.Name} = new {p.TypeNameForTypeof}();");
+                sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(rc_{p.Name}, context, {nd});");
+                sb.AppendLine($"{i}    {a} = rc_{p.Name};");
+                sb.AppendLine($"{i}}}");
             }
             else
             {
-                // ZERO branches — tc is always Object, just call ReadObject
-                sb.AppendLine($"{i}{a} = {cast}{reader}.Instance.ReadObject(context, {nd}, -1)!;");
+                // ZERO branches — tc is always Object
+                sb.AppendLine($"{i}{{");
+                sb.AppendLine($"{i}    var rc_{p.Name} = new {p.TypeNameForTypeof}();");
+                sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(rc_{p.Name}, context, {nd});");
+                sb.AppendLine($"{i}    {a} = rc_{p.Name};");
+                sb.AppendLine($"{i}}}");
             }
         }
         else
         {
             // Ref tracking possible — Object/ObjectRefFirst/ObjectRef dispatch
+            // Inline: parent creates instance + handles cache registration
             sb.AppendLine($"{i}if ({tc} == BinaryTypeCode.Object)");
-            sb.AppendLine($"{i}    {a} = {cast}{reader}.Instance.ReadObject(context, {nd}, -1)!;");
+            sb.AppendLine($"{i}{{");
+            sb.AppendLine($"{i}    var rc_{p.Name} = new {p.TypeNameForTypeof}();");
+            sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(rc_{p.Name}, context, {nd});");
+            sb.AppendLine($"{i}    {a} = rc_{p.Name};");
+            sb.AppendLine($"{i}}}");
             sb.AppendLine($"{i}else if ({tc} == BinaryTypeCode.ObjectRefFirst)");
-            sb.AppendLine($"{i}    {a} = {cast}{reader}.Instance.ReadObject(context, {nd}, (int)context.ReadVarUInt())!;");
+            sb.AppendLine($"{i}{{");
+            sb.AppendLine($"{i}    var ci_{p.Name} = (int)context.ReadVarUInt();");
+            sb.AppendLine($"{i}    var rc_{p.Name} = new {p.TypeNameForTypeof}();");
+            sb.AppendLine($"{i}    context.RegisterInternedValueAt(ci_{p.Name}, rc_{p.Name});");
+            sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(rc_{p.Name}, context, {nd});");
+            sb.AppendLine($"{i}    {a} = rc_{p.Name};");
+            sb.AppendLine($"{i}}}");
             if (p.IsNullable)
                 sb.AppendLine($"{i}else if ({tc} == BinaryTypeCode.Null) {{ /* null */ }}");
             sb.AppendLine($"{i}else if ({tc} == BinaryTypeCode.ObjectRef)");
@@ -2219,9 +2246,19 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             sb.AppendLine($"{i}        var {vtc} = context.ReadByte();");
             sb.AppendLine($"{i}        {valType}? dv_{s} = null;");
             sb.AppendLine($"{i}        if ({vtc} == BinaryTypeCode.Object)");
-            sb.AppendLine($"{i}            dv_{s} = ({valType}){valReader}.Instance.ReadObject(context, nd_{s}, -1)!;");
+            sb.AppendLine($"{i}        {{");
+            sb.AppendLine($"{i}            var rv_{s} = new {valType}();");
+            sb.AppendLine($"{i}            {valReader}.Instance.ReadProperties(rv_{s}, context, nd_{s});");
+            sb.AppendLine($"{i}            dv_{s} = rv_{s};");
+            sb.AppendLine($"{i}        }}");
             sb.AppendLine($"{i}        else if ({vtc} == BinaryTypeCode.ObjectRefFirst)");
-            sb.AppendLine($"{i}            dv_{s} = ({valType}){valReader}.Instance.ReadObject(context, nd_{s}, (int)context.ReadVarUInt())!;");
+            sb.AppendLine($"{i}        {{");
+            sb.AppendLine($"{i}            var rci_{s} = (int)context.ReadVarUInt();");
+            sb.AppendLine($"{i}            var rv_{s} = new {valType}();");
+            sb.AppendLine($"{i}            context.RegisterInternedValueAt(rci_{s}, rv_{s});");
+            sb.AppendLine($"{i}            {valReader}.Instance.ReadProperties(rv_{s}, context, nd_{s});");
+            sb.AppendLine($"{i}            dv_{s} = rv_{s};");
+            sb.AppendLine($"{i}        }}");
             sb.AppendLine($"{i}        else if ({vtc} == BinaryTypeCode.ObjectRef)");
             sb.AppendLine($"{i}            dv_{s} = ({valType})context.GetInternedObject((int)context.ReadVarUInt())!;");
             sb.AppendLine($"{i}        else if ({vtc} != BinaryTypeCode.Null)");
@@ -2376,7 +2413,7 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             sb.AppendLine($"{i}    for (var ri_{s} = 0; ri_{s} < cnt_{s}; ri_{s}++)");
             sb.AppendLine($"{i}    {{");
             if (isComplexElement)
-                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), $"({elemType})", $"ri_{s}", s, i + "        ", isArray: true, p.ElementNeedsRefScan);
+                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), elemType, $"({elemType})", $"ri_{s}", s, i + "        ", isArray: true, p.ElementNeedsRefScan);
             else
                 EmitReadNonComplexCollectionElement(sb, p, $"ri_{s}", s, i + "        ", isArray: true, null);
             sb.AppendLine($"{i}    }}");
@@ -2391,7 +2428,7 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             sb.AppendLine($"{i}    for (var ri_{s} = 0; ri_{s} < cnt_{s}; ri_{s}++)");
             sb.AppendLine($"{i}    {{");
             if (isComplexElement)
-                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), $"({elemType})", $"ri_{s}", s, i + "        ", isArray: false, p.ElementNeedsRefScan, p.CollectionAddMethod);
+                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), elemType, $"({elemType})", $"ri_{s}", s, i + "        ", isArray: false, p.ElementNeedsRefScan, p.CollectionAddMethod);
             else
                 EmitReadNonComplexCollectionElement(sb, p, $"ri_{s}", s, i + "        ", isArray: false, p.CollectionAddMethod);
             sb.AppendLine($"{i}    }}");
@@ -2402,7 +2439,7 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             sb.AppendLine($"{i}    for (var ri_{s} = 0; ri_{s} < cnt_{s}; ri_{s}++)");
             sb.AppendLine($"{i}    {{");
             if (isComplexElement)
-                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), $"({elemType})", $"ri_{s}", s, i + "        ", isArray: false, p.ElementNeedsRefScan);
+                EmitReadCollectionElement(sb, p.ElementWriterClassName!.Replace("_GeneratedWriter", "_GeneratedReader"), elemType, $"({elemType})", $"ri_{s}", s, i + "        ", isArray: false, p.ElementNeedsRefScan);
             else
                 EmitReadNonComplexCollectionElement(sb, p, $"ri_{s}", s, i + "        ", isArray: false, null);
             sb.AppendLine($"{i}    }}");
@@ -2417,32 +2454,49 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
     /// SGen reader = non-metadata mode → no ObjectWithMetadata fallback.
     /// !needsRefScan → only Object/Null possible → 1 branch per element.
     /// </summary>
-    private static void EmitReadCollectionElement(StringBuilder sb, string reader, string elemCast, string indexVar, string propSuffix, string i, bool isArray, bool needsRefScan, string? addMethod = null)
+    private static void EmitReadCollectionElement(StringBuilder sb, string reader, string elemTypeName, string elemCast, string indexVar, string propSuffix, string i, bool isArray, bool needsRefScan, string? addMethod = null)
     {
         var etc = $"etc_{propSuffix}";
         sb.AppendLine($"{i}var {etc} = context.ReadByte();");
 
         var addCall = addMethod ?? "Add";
         var assignNull = isArray ? $"col_{propSuffix}[{indexVar}] = null!;" : $"col_{propSuffix}.{addCall}(null!);";
-        var assignExpr = isArray ? $"col_{propSuffix}[{indexVar}] = " : $"col_{propSuffix}.{addCall}(";
-        var assignEnd = isArray ? ";" : ");";
+        var assignExpr = isArray ? $"col_{propSuffix}[{indexVar}] = re_{propSuffix};" : $"col_{propSuffix}.{addCall}(re_{propSuffix});";
 
         if (!needsRefScan)
         {
-            // No ref tracking → only Object or Null in stream — 1 branch
+            // No ref tracking → only Object or Null in stream — inline ReadProperties
             sb.AppendLine($"{i}if ({etc} == BinaryTypeCode.Null) {{ {assignNull} }}");
-            sb.AppendLine($"{i}else {assignExpr}{elemCast}{reader}.Instance.ReadObject(context, nd_{propSuffix}, -1)!{assignEnd}");
+            sb.AppendLine($"{i}else");
+            sb.AppendLine($"{i}{{");
+            sb.AppendLine($"{i}    var re_{propSuffix} = new {elemTypeName}();");
+            sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(re_{propSuffix}, context, nd_{propSuffix});");
+            sb.AppendLine($"{i}    {assignExpr}");
+            sb.AppendLine($"{i}}}");
         }
         else
         {
-            // Object hot path first, then ref markers
+            // Object hot path first, then ref markers — inline ReadProperties
             sb.AppendLine($"{i}if ({etc} == BinaryTypeCode.Object)");
-            sb.AppendLine($"{i}    {assignExpr}{elemCast}{reader}.Instance.ReadObject(context, nd_{propSuffix}, -1)!{assignEnd}");
+            sb.AppendLine($"{i}{{");
+            sb.AppendLine($"{i}    var re_{propSuffix} = new {elemTypeName}();");
+            sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(re_{propSuffix}, context, nd_{propSuffix});");
+            sb.AppendLine($"{i}    {assignExpr}");
+            sb.AppendLine($"{i}}}");
             sb.AppendLine($"{i}else if ({etc} == BinaryTypeCode.ObjectRefFirst)");
-            sb.AppendLine($"{i}    {assignExpr}{elemCast}{reader}.Instance.ReadObject(context, nd_{propSuffix}, (int)context.ReadVarUInt())!{assignEnd}");
+            sb.AppendLine($"{i}{{");
+            sb.AppendLine($"{i}    var ci_{propSuffix} = (int)context.ReadVarUInt();");
+            sb.AppendLine($"{i}    var re_{propSuffix} = new {elemTypeName}();");
+            sb.AppendLine($"{i}    context.RegisterInternedValueAt(ci_{propSuffix}, re_{propSuffix});");
+            sb.AppendLine($"{i}    {reader}.Instance.ReadProperties(re_{propSuffix}, context, nd_{propSuffix});");
+            sb.AppendLine($"{i}    {assignExpr}");
+            sb.AppendLine($"{i}}}");
             sb.AppendLine($"{i}else if ({etc} == BinaryTypeCode.Null) {{ {assignNull} }}");
             sb.AppendLine($"{i}else if ({etc} == BinaryTypeCode.ObjectRef)");
-            sb.AppendLine($"{i}    {assignExpr}{elemCast}context.GetInternedObject((int)context.ReadVarUInt())!{assignEnd}");
+            if (isArray)
+                sb.AppendLine($"{i}    col_{propSuffix}[{indexVar}] = {elemCast}context.GetInternedObject((int)context.ReadVarUInt())!;");
+            else
+                sb.AppendLine($"{i}    col_{propSuffix}.{addCall}({elemCast}context.GetInternedObject((int)context.ReadVarUInt())!);");
         }
     }
 
diff --git a/AyCode.Core/Serializers/Binaries/IGeneratedBinaryReader.cs b/AyCode.Core/Serializers/Binaries/IGeneratedBinaryReader.cs
index 5e63aee..675e1a9 100644
--- a/AyCode.Core/Serializers/Binaries/IGeneratedBinaryReader.cs
+++ b/AyCode.Core/Serializers/Binaries/IGeneratedBinaryReader.cs
@@ -26,4 +26,16 @@ internal interface IGeneratedBinaryReader
     /// <returns>The deserialized object, or null if creation failed.</returns>
     object? ReadObject<TInput>(AcBinaryDeserializer.BinaryDeserializationContext<TInput> context, int depth, int cacheIndex)
         where TInput : struct, IBinaryInputBase;
+
+    /// <summary>
+    /// Reads all properties into an existing instance (no object creation, no cache registration).
+    /// Called from parent SGen reader after instance creation + cache registration.
+    /// Mirrors WriteProperties: parent handles lifecycle, child handles data.
+    /// </summary>
+    /// <param name="value">The pre-created instance to populate. Implementation casts to the concrete type.</param>
+    /// <param name="context">The deserialization context (owns buffer, position, options).</param>
+    /// <param name="depth">Current depth in the object graph.</param>
+    /// <typeparam name="TInput">Input strategy (ArrayBinaryInput or SequenceBinaryInput).</typeparam>
+    void ReadProperties<TInput>(object value, AcBinaryDeserializer.BinaryDeserializationContext<TInput> context, int depth)
+        where TInput : struct, IBinaryInputBase;
 }