diff --git a/src/agentscope/manager/_model.py b/src/agentscope/manager/_model.py
index 422293958..0f63f14be 100644
--- a/src/agentscope/manager/_model.py
+++ b/src/agentscope/manager/_model.py
@@ -100,16 +100,16 @@ def load_model_configs(
                 f"list of dicts), but got {type(model_configs)}",
             )
 
-        format_configs = _ModelConfig.format_configs(configs=cfgs)
+        formatted_configs = _format_configs(configs=cfgs)
 
         # check if name is unique
-        for cfg in format_configs:
-            if cfg.config_name in self.model_configs:
+        for cfg in formatted_configs:
+            if cfg["config_name"] in self.model_configs:
                 logger.warning(
-                    f"config_name [{cfg.config_name}] already exists.",
+                    f"config_name [{cfg['config_name']}] already exists.",
                 )
                 continue
-            self.model_configs[cfg.config_name] = cfg
+            self.model_configs[cfg["config_name"]] = cfg
 
         # print the loaded model configs
         logger.info(
@@ -137,7 +137,7 @@ def get_model_by_config_name(self, config_name: str) -> ModelWrapperBase:
                 f"Cannot find [{config_name}] in loaded configurations.",
             )
 
-        model_type = config.model_type
+        model_type = config["model_type"]
 
         kwargs = {k: v for k, v in config.items() if k != "model_type"}
 
@@ -164,55 +164,28 @@ def flush(self) -> None:
         self.clear_model_configs()
 
 
-class _ModelConfig(dict):
-    """Base class for model config."""
+def _format_configs(
+    configs: Union[Sequence[dict], dict],
+) -> Sequence:
+    """Check the format of model configs.
 
-    __getattr__ = dict.__getitem__
-    __setattr__ = dict.__setitem__
+    Args:
+        configs (Union[Sequence[dict], dict]): configs in dict format.
 
-    def __init__(
-        self,
-        config_name: str,
-        model_type: str = None,
-        **kwargs: Any,
-    ):
-        """Initialize the config with the given arguments, and checking the
-        type of the arguments.
-
-        Args:
-            config_name (`str`): A unique name of the model config.
-            model_type (`str`, optional): The class name (or its model type) of
-                the generated model wrapper. Defaults to None.
-
-        Raises:
-            `ValueError`: If `config_name` is not provided.
-        """
-        if config_name is None:
-            raise ValueError("The `config_name` field is required for Cfg")
-        if model_type is None:
+    Returns:
+        Sequence[dict]: converted ModelConfig list.
+    """
+    if isinstance(configs, dict):
+        configs = [configs]
+    for config in configs:
+        if "config_name" not in config:
+            raise ValueError(
+                "The `config_name` field is required for Cfg",
+            )
+        if "model_type" not in config:
             logger.warning(
-                f"`model_type` is not provided in config [{config_name}],"
+                "`model_type` is not provided in config"
+                f"[{config['config_name']}],"
                 " use `PostAPIModelWrapperBase` by default.",
             )
-        super().__init__(
-            config_name=config_name,
-            model_type=model_type,
-            **kwargs,
-        )
-
-    @classmethod
-    def format_configs(
-        cls,
-        configs: Union[Sequence[dict], dict],
-    ) -> Sequence:
-        """Covert config dicts into a list of _ModelConfig.
-
-        Args:
-            configs (Union[Sequence[dict], dict]): configs in dict format.
-
-        Returns:
-            Sequence[_ModelConfig]: converted ModelConfig list.
-        """
-        if isinstance(configs, dict):
-            return [_ModelConfig(**configs)]
-        return [_ModelConfig(**cfg) for cfg in configs]
+    return configs