diff --git a/src/Luban.Job.Cfg/Source/Defs/TTypeTemplateExtends.cs b/src/Luban.Job.Cfg/Source/Defs/TTypeTemplateExtends.cs
index 800f6cc..8af03d2 100644
--- a/src/Luban.Job.Cfg/Source/Defs/TTypeTemplateExtends.cs
+++ b/src/Luban.Job.Cfg/Source/Defs/TTypeTemplateExtends.cs
@@ -12,7 +12,7 @@ namespace Luban.Job.Cfg.Defs
         {
             if (type.IsNullable)
             {
-                return $"{{ var _j = {bufName}.GetProperty(\"{jsonFieldName}\"); if (_j.ValueKind != JsonValueKind.Null) {{ {type.Apply(TypeVisitors.CsJsonDeserialize.Ins, "_j", fieldName)} }} else {{ {fieldName} = null; }} }}";
+                return $"{{ if ({bufName}.TryGetProperty(\"{jsonFieldName}\", out var _j) && _j.ValueKind != JsonValueKind.Null) {{ {type.Apply(TypeVisitors.CsJsonDeserialize.Ins, "_j", fieldName)} }} else {{ {fieldName} = null; }} }}";
             }
             else
             {
@@ -156,14 +156,52 @@ namespace Luban.Job.Cfg.Defs
             }
         }
 
-        public static string Py3Deserialize(string fieldName, string jsonFieldName, TType type)
+        public static string Py3DeserializeValue(string fieldName, string jsonVarName, TType type)
         {
-            return type.Apply(PyDeserializeVisitor.Py3Ins, $"{jsonFieldName}", fieldName);
+            if (type.IsNullable)
+            {
+                return $"if {jsonVarName} != None: {type.Apply(PyUnderingDeserializeVisitor.Py3Ins, jsonVarName, fieldName)}";
+            }
+            else
+            {
+                return type.Apply(PyUnderingDeserializeVisitor.Py3Ins, jsonVarName, fieldName);
+            }
         }
 
-        public static string Py27Deserialize(string fieldName, string jsonFieldName, TType type)
+        public static string Py27DeserializeValue(string fieldName, string jsonVarName, TType type)
         {
-            return type.Apply(PyDeserializeVisitor.Py27Ins, $"{jsonFieldName}", fieldName);
+            if (type.IsNullable)
+            {
+                return $"if {jsonVarName} != None: {type.Apply(PyUnderingDeserializeVisitor.Py27Ins, jsonVarName, fieldName)}";
+            }
+            else
+            {
+                return type.Apply(PyUnderingDeserializeVisitor.Py3Ins, jsonVarName, fieldName);
+            }
+        }
+
+        public static string Py3DeserializeField(string fieldName, string jsonVarName, string jsonFieldName, TType type)
+        {
+            if (type.IsNullable)
+            {
+                return $"if {jsonVarName}.get('{jsonFieldName}') != None: {type.Apply(PyUnderingDeserializeVisitor.Py3Ins, $"{jsonVarName}['{jsonFieldName}']", fieldName)}";
+            }
+            else
+            {
+                return type.Apply(PyUnderingDeserializeVisitor.Py3Ins, $"{jsonVarName}['{jsonFieldName}']", fieldName);
+            }
+        }
+
+        public static string Py27DeserializeField(string fieldName, string jsonVarName, string jsonFieldName, TType type)
+        {
+            if (type.IsNullable)
+            {
+                return $"if {jsonVarName}.get('{jsonFieldName}') != None: {type.Apply(PyUnderingDeserializeVisitor.Py3Ins, $"{jsonVarName}['{jsonFieldName}']", fieldName)}";
+            }
+            else
+            {
+                return type.Apply(PyUnderingDeserializeVisitor.Py27Ins, $"{jsonVarName}['{jsonFieldName}']", fieldName);
+            }
         }
     }
 }
diff --git a/src/Luban.Job.Cfg/Source/Generate/Python3CodeJsonRender.cs b/src/Luban.Job.Cfg/Source/Generate/Python3CodeJsonRender.cs
index 0b327cb..670e6de 100644
--- a/src/Luban.Job.Cfg/Source/Generate/Python3CodeJsonRender.cs
+++ b/src/Luban.Job.Cfg/Source/Generate/Python3CodeJsonRender.cs
@@ -48,10 +48,7 @@ class {{name}} {{if parent_def_type}}({{parent_def_type.py_full_name}}){{else if
         {{parent_def_type.py_full_name}}.__init__(self, _json_)
         {{~end~}}
         {{~ for field in export_fields ~}}
-            {{~if !field.ctype.is_nullable~}}
-        if _json_['{{field.name}}'] == None: raise Exception()
-            {{~end~}}
-        {{py3_deserialize ('self.' + field.py_style_name) ('_json_[""' + field.name + '""]') field.ctype}}
+        {{py3_deserialize_field ('self.' + field.py_style_name) '_json_' field.name field.ctype}}
         {{~end~}}
         {{~if export_fields.empty?}}
         pass
@@ -83,7 +80,7 @@ class {{name}}:
         self._dataList = []
         
         for _json2_ in _json_:
-            {{py3_deserialize '_v' '_json2_' value_type}}
+            {{py3_deserialize_value '_v' '_json2_' value_type}}
             self._dataList.append(_v)
             self._dataMap[_v.{{x.index_field.py_style_name}}] = _v
 
@@ -96,7 +93,7 @@ class {{name}}:
 
     def __init__(self, _json_):
         if (len(_json_) != 1): raise Exception('table mode=one, but size != 1')
-        {{py3_deserialize 'self._data' '_json_[0]' value_type}}
+        {{py3_deserialize_value 'self._data' '_json_[0]' value_type}}
 
     def getData(self) : return self._data
 
diff --git a/src/Luban.Job.Cfg/Source/Generate/PythonCodeRenderBase.cs b/src/Luban.Job.Cfg/Source/Generate/PythonCodeRenderBase.cs
index 1b32d0e..a876fd2 100644
--- a/src/Luban.Job.Cfg/Source/Generate/PythonCodeRenderBase.cs
+++ b/src/Luban.Job.Cfg/Source/Generate/PythonCodeRenderBase.cs
@@ -55,7 +55,7 @@ class {{x.py_full_name}}:
 {{comment}}
 '''
 {{~end~}}
-class {{py_full_name}}:
+class {{py_full_name}}(Enum):
     {{~ for item in items ~}}
 {{~if item.comment != '' ~}}
     '''