diff --git a/frameworks/bridge/arkts_frontend/koala_mirror/interop/src/arkts/SerializerBase.ts b/frameworks/bridge/arkts_frontend/koala_mirror/interop/src/arkts/SerializerBase.ts
index 992546fcf976c6b530eb47543fb28a73cfbe5fdc..799df6afb548750c47f0ea3ca1311fec083bd907 100644
--- a/frameworks/bridge/arkts_frontend/koala_mirror/interop/src/arkts/SerializerBase.ts
+++ b/frameworks/bridge/arkts_frontend/koala_mirror/interop/src/arkts/SerializerBase.ts
@@ -392,7 +392,7 @@ export class SerializerBase implements Disposable {
         this._position = newPos
 
         if (value == undefined)
-            unsafeMemory.writeInt8(pos, Tags.UNDEFINED);
+            unsafeMemory.writeInt8(pos, Tags.UNDEFINED.valueOf().toByte());
         else if (value == true)
             unsafeMemory.writeInt8(pos, VALUE_TRUE.toByte());
         else if (value == false)
diff --git a/frameworks/bridge/arkts_frontend/koala_projects/interop/src/arkts/SerializerBase.ts b/frameworks/bridge/arkts_frontend/koala_projects/interop/src/arkts/SerializerBase.ts
index 992546fcf976c6b530eb47543fb28a73cfbe5fdc..799df6afb548750c47f0ea3ca1311fec083bd907 100644
--- a/frameworks/bridge/arkts_frontend/koala_projects/interop/src/arkts/SerializerBase.ts
+++ b/frameworks/bridge/arkts_frontend/koala_projects/interop/src/arkts/SerializerBase.ts
@@ -392,7 +392,7 @@ export class SerializerBase implements Disposable {
         this._position = newPos
 
         if (value == undefined)
-            unsafeMemory.writeInt8(pos, Tags.UNDEFINED);
+            unsafeMemory.writeInt8(pos, Tags.UNDEFINED.valueOf().toByte());
         else if (value == true)
             unsafeMemory.writeInt8(pos, VALUE_TRUE.toByte());
         else if (value == false)