diff --git a/fastNLP/models/bert.py b/fastNLP/models/bert.py
index ad7750ec..3afccc14 100644
--- a/fastNLP/models/bert.py
+++ b/fastNLP/models/bert.py
@@ -10,6 +10,7 @@ from .base_model import BaseModel
 from ..core.const import Const
 from ..modules.encoder import BertModel
 from ..modules.encoder.bert import BertConfig, CONFIG_FILE
+from ..core.utils import seq_len_to_mask
 
 
 class BertForSequenceClassification(BaseModel):
@@ -70,6 +71,10 @@ class BertForSequenceClassification(BaseModel):
         return model
 
     def forward(self, words, seq_len=None, target=None):
+        if seq_len is None:
+            seq_len = torch.ones_like(words, dtype=words.dtype, device=words.device)
+        if len(seq_len.size()) + 1 == len(words.size()):
+            seq_len = seq_len_to_mask(seq_len, max_len=words.size(-1))
         _, pooled_output = self.bert(words, attention_mask=seq_len, output_all_encoded_layers=False)
         pooled_output = self.dropout(pooled_output)
         logits = self.classifier(pooled_output)
diff --git a/test/models/test_bert.py b/test/models/test_bert.py
index 05ee6d5a..40b98c81 100644
--- a/test/models/test_bert.py
+++ b/test/models/test_bert.py
@@ -2,7 +2,8 @@ import unittest
 
 import torch
 
-from fastNLP.models.bert import *
+from fastNLP.models.bert import BertForSequenceClassification, BertForQuestionAnswering, \
+    BertForTokenClassification, BertForMultipleChoice
 
 
 class TestBert(unittest.TestCase):
@@ -14,9 +15,14 @@ class TestBert(unittest.TestCase):
 
         input_ids = torch.LongTensor([[31, 51, 99], [15, 5, 0]])
         input_mask = torch.LongTensor([[1, 1, 1], [1, 1, 0]])
-        token_type_ids = torch.LongTensor([[0, 0, 1], [0, 1, 0]])
 
-        pred = model(input_ids, token_type_ids, input_mask)
+        pred = model(input_ids, input_mask)
+        self.assertTrue(isinstance(pred, dict))
+        self.assertTrue(Const.OUTPUT in pred)
+        self.assertEqual(tuple(pred[Const.OUTPUT].shape), (2, 2))
+
+        input_mask = torch.LongTensor([3, 2])
+        pred = model(input_ids, input_mask)
         self.assertTrue(isinstance(pred, dict))
         self.assertTrue(Const.OUTPUT in pred)
         self.assertEqual(tuple(pred[Const.OUTPUT].shape), (2, 2))