diff --git a/fastNLP/core/losses.py b/fastNLP/core/losses.py
index aa1ffb89..9306f9f9 100644
--- a/fastNLP/core/losses.py
+++ b/fastNLP/core/losses.py
@@ -76,14 +76,15 @@ class NewLoss(LossBase):
 class LossInForward(LossBase):
     def __init__(self, loss_key='loss'):
         super().__init__()
-
         self.loss_key = loss_key
 
-    def get_loss(self, *args, **kwargs):
-        pass
+    def get_loss(self, **kwargs):
+        if self.loss_key not in kwargs:
+            pass
 
     def __call__(self, output_dict, predict_dict):
-        pass
+
+        return self.get_loss(**output_dict)
 
 
 def _prepare_losser(losser):