diff --git a/edustudio/utils/callback/callbacks/history.py b/edustudio/utils/callback/callbacks/history.py
index 5b371dc..886d00b 100644
--- a/edustudio/utils/callback/callbacks/history.py
+++ b/edustudio/utils/callback/callbacks/history.py
@@ -8,12 +8,7 @@
 import json
 import os
 import numpy as np
-
-class NumpyEncoder(json.JSONEncoder):
-    def default(self, obj):
-        if isinstance(obj, np.ndarray):
-            return obj.tolist()
-        return json.JSONEncoder.default(self, obj)
+from edustudio.utils.common import NumpyEncoder
 
 
 class History(Callback):
diff --git a/edustudio/utils/common/__init__.py b/edustudio/utils/common/__init__.py
index 1a735d6..89dd369 100644
--- a/edustudio/utils/common/__init__.py
+++ b/edustudio/utils/common/__init__.py
@@ -4,5 +4,5 @@
 
 
 from .commonUtil import PathUtil, IDUtil, tensor2npy, tensor2cpu, IOUtil, set_same_seeds, get_gpu_usage, DecoratorTimer
-from .configUtil import UnifyConfig
+from .configUtil import UnifyConfig, NumpyEncoder
 from .loggerUtil import Logger