diff --git a/python/paddle/fluid/framework.py b/python/paddle/fluid/framework.py
index a4400d6272f9ef517a9a57595abcc3e5fd6ec1de..5747de7ddd2d492cc509aeec8fa97f8635fef3ab 100644
--- a/python/paddle/fluid/framework.py
+++ b/python/paddle/fluid/framework.py
@@ -1160,19 +1160,22 @@ def grad_var_name(var_name):
 
 def convert_np_dtype_to_dtype_(np_dtype):
     """
-    Convert the data type in numpy to the data type in Paddle
+    Convert the data type in numpy to the data type in Paddle.
 
     Args:
-        np_dtype(np.dtype): the data type in numpy.
+        np_dtype (np.dtype|str): The data type in numpy or valid data type
+            string.
 
     Returns:
-        core.VarDesc.VarType: the data type in Paddle.
+        core.VarDesc.VarType: The data type in Paddle.
 
     """
-    if np_dtype == "bfloat16":
+    # Convert the data type string to numpy data type.
+    if isinstance(np_dtype, str) and np_dtype == "bfloat16":
         dtype = np.uint16
     else:
         dtype = np.dtype(np_dtype)
+
     if dtype == np.float32:
         return core.VarDesc.VarType.FP32
     elif dtype == np.float64:
diff --git a/python/paddle/fluid/tests/unittests/npu/test_tril_triu_op_npu.py b/python/paddle/fluid/tests/unittests/npu/test_tril_triu_op_npu.py
index f62c5b47d5ab0cc89c4ec6e17e535b8d5e5750ce..2bd374fe6d0e7acdb6a327c11ffc51ea39018660 100644
--- a/python/paddle/fluid/tests/unittests/npu/test_tril_triu_op_npu.py
+++ b/python/paddle/fluid/tests/unittests/npu/test_tril_triu_op_npu.py
@@ -135,7 +135,7 @@ for _op_type in ['tril', 'triu']:
 
 
 class TestTrilTriuOpAPI(unittest.TestCase):
-    """ test case by using API and has -1 dimension 
+    """ test case by using API and has -1 dimension
     """
 
     def test_api(self):