diff --git a/mindarmour/utils/_check_param.py b/mindarmour/utils/_check_param.py
index 9f12f2f..b8ebc54 100644
--- a/mindarmour/utils/_check_param.py
+++ b/mindarmour/utils/_check_param.py
@@ -218,14 +218,14 @@ def normalize_value(value, norm_level):
 
     Args:
         value (numpy.ndarray): Inputs.
-        norm_level (Union[int, str]): Normalized level. Option: [1, 2, np.inf, '1', '2', 'inf', 'l1', 'l2']
+        norm_level (Union[int, str]): Normalized level. Option: [1, 2, '1', '2', 'l1', 'l2', np.inf, 'np.inf',
+            'linf', 'inf'].
 
     Returns:
         numpy.ndarray, normalized value.
 
     Raises:
-        NotImplementedError: If norm_level is not in [1, 2 , np.inf, '1', '2',
-            'inf', 'l1', 'l2']
+        NotImplementedError: If norm_level is not in [1, 2, '1', '2', 'l1', 'l2', np.inf, 'np.inf', 'linf', 'inf'].
     """
     norm_level = check_norm_level(norm_level)
     ori_shape = value.shape
@@ -237,7 +237,7 @@ def normalize_value(value, norm_level):
     elif norm_level in (2, '2', 'l2'):
         norm = np.linalg.norm(value_reshape, ord=2, axis=1, keepdims=True) + avoid_zero_div
         norm_value = value_reshape / norm
-    elif norm_level in (np.inf, 'inf', 'np.inf'):
+    elif norm_level in (np.inf, 'inf', 'np.inf', 'linf'):
         norm = np.max(abs(value_reshape), axis=1, keepdims=True) + avoid_zero_div
         norm_value = value_reshape / norm
     else: