diff --git a/metagpt/config2.py b/metagpt/config2.py
index 6b6f4935b..243a98078 100644
--- a/metagpt/config2.py
+++ b/metagpt/config2.py
@@ -156,21 +156,21 @@ def merge_dict(dicts: Iterable[Dict]) -> Dict:
 class ConfigMixin(BaseModel):
     """Mixin class for configurable objects"""
 
-    _config: Optional[Config] = None
+    config: Optional[Config] = None
 
-    def __init__(self, config: Optional[Config] = None):
-        super().__init__()
-        self._config = config
+    def __init__(self, config: Optional[Config] = None, **kwargs):
+        """Initialize with config"""
+        super().__init__(**kwargs)
+        self.set_config(config)
 
-    def try_set_parent_config(self, parent_config):
+    def set(self, k, v, override=False):
         """Try to set parent config if not set"""
-        if self._config is None:
-            self._config = parent_config
+        if override or not self.__dict__.get(k):
+            self.__dict__[k] = v
 
-    @property
-    def config(self):
-        """Get config"""
-        return self._config
+    def set_config(self, config: Config, override=False):
+        """Set config"""
+        self.set("config", config, override)
 
 
 config = Config.default()
diff --git a/tests/metagpt/test_config.py b/tests/metagpt/test_config.py
index 5492d1726..81673fc65 100644
--- a/tests/metagpt/test_config.py
+++ b/tests/metagpt/test_config.py
@@ -29,27 +29,56 @@ def test_config_from_dict():
     assert cfg.llm["default"].api_key == "mock_api_key"
 
 
-class NewModel(ConfigMixin, BaseModel):
+class ModelX(ConfigMixin, BaseModel):
     a: str = "a"
     b: str = "b"
 
 
+class WTFMixin(BaseModel):
+    c: str = "c"
+    d: str = "d"
+
+    def __init__(self, **data):
+        super().__init__(**data)
+
+
+class ModelY(WTFMixin, ModelX):
+    def __init__(self, **data):
+        super().__init__(**data)
+
+
 def test_config_mixin_1():
-    new_model = NewModel()
+    new_model = ModelX()
     assert new_model.a == "a"
     assert new_model.b == "b"
-    assert new_model._config == new_model.config
-    assert new_model._config is None
 
 
 def test_config_mixin_2():
     i = Config(llm={"default": mock_llm_config})
     j = Config(llm={"new": mock_llm_config})
-    obj = NewModel(config=i)
+    obj = ModelX(config=i)
     assert obj.config == i
-    assert obj._config == i
     assert obj.config.llm["default"] == mock_llm_config
 
-    obj.try_set_parent_config(j)
+    obj.set_config(j)
     # obj already has a config, so it will not be set
     assert obj.config == i
+
+
+def test_config_mixin_3():
+    """Test config mixin with multiple inheritance"""
+    i = Config(llm={"default": mock_llm_config})
+    j = Config(llm={"new": mock_llm_config})
+    obj = ModelY(config=i)
+    assert obj.config == i
+    assert obj.config.llm["default"] == mock_llm_config
+
+    obj.set_config(j)
+    # obj already has a config, so it will not be set
+    assert obj.config == i
+    assert obj.config.llm["default"] == mock_llm_config
+
+    assert obj.a == "a"
+    assert obj.b == "b"
+    assert obj.c == "c"
+    assert obj.d == "d"