diff --git a/mindspore/train/callback/_checkpoint.py b/mindspore/train/callback/_checkpoint.py
index da8528b659..bb79c75a6d 100644
--- a/mindspore/train/callback/_checkpoint.py
+++ b/mindspore/train/callback/_checkpoint.py
@@ -235,7 +235,9 @@ class ModelCheckpoint(Callback):
         self._last_time_for_keep = time.time()
         self._last_triggered_step = 0
 
-        Validator.check_file_name_by_regular(prefix)
+        if not isinstance(prefix, str) or prefix.find('/') >= 0:
+            raise ValueError("Prefix {} for checkpoint file name invalid, "
+                             "please check and correct it and then continue.".format(prefix))
         self._prefix = prefix
 
         if directory is not None:
diff --git a/mindspore/train/serialization.py b/mindspore/train/serialization.py
index 4b8025d2fe..46039952ee 100644
--- a/mindspore/train/serialization.py
+++ b/mindspore/train/serialization.py
@@ -53,7 +53,10 @@ tensor_to_np_type = {"Int8": np.int8, "Uint8": np.uint8, "Int16": np.int16, "Uin
                      "Float16": np.float16, "Float32": np.float32, "Float64": np.float64, "Bool": np.bool_}
 
 _ckpt_mutex = Lock()
-SLICE_SIZE = 512 * 1024 * 1024
+
+# unit is KB
+SLICE_SIZE = 512 * 1024
+PROTO_LIMIT_SIZE = 1024 * 1024 * 2
 TOTAL_SAVE = 1024 * 1024
 
 
@@ -126,7 +129,7 @@ def _exec_save(ckpt_file_name, data_list):
                 os.remove(ckpt_file_name)
             with open(ckpt_file_name, "ab") as f:
                 for name, value in data_list.items():
-                    data_size = value[2].nbytes
+                    data_size = value[2].nbytes / 1024
                     if data_size > SLICE_SIZE:
                         slice_count = math.ceil(data_size / SLICE_SIZE)
                         param_slice_list = np.array_split(value[2], slice_count)
@@ -636,6 +639,10 @@ def _export(net, file_name, file_format, *inputs):
             file_name += ".air"
         _executor.export(file_name, graph_id)
     elif file_format == 'ONNX':
+        total_size = _calculation_net_size(net)
+        if total_size > PROTO_LIMIT_SIZE:
+            raise RuntimeError('Export onnx model failed. Network size is: {}G, it exceeded the protobuf: {}G limit.'
+                               .format(total_size/1024/1024, PROTO_LIMIT_SIZE/1024/1024))
         phase_name = 'export.onnx'
         graph_id, _ = _executor.compile(net, *inputs, phase=phase_name, do_convert=False)
         onnx_stream = _executor._get_func_graph_proto(net, graph_id)
@@ -1213,3 +1220,13 @@ def _merge_and_split(sliced_params, train_strategy, predict_strategy):
     layerwise_parallel = merged_param.layerwise_parallel
     split_param = Parameter(split_tensor, param_name, requires_grad, layerwise_parallel)
     return split_param
+
+
+def _calculation_net_size(net):
+    """Calculate the size of parameters in the network."""
+    data_total = 0
+    net_dict = net.parameters_dict()
+    for name in net_dict:
+        data_total += sys.getsizeof(net_dict[name].data.asnumpy().tobytes()) / 1024
+
+    return data_total