diff --git a/modeling_chatglm.py b/modeling_chatglm.py
index 65e378e..bed7e6f 100644
--- a/modeling_chatglm.py
+++ b/modeling_chatglm.py
@@ -769,7 +769,7 @@ class ChatGLMModel(ChatGLMPreTrainedModel):
         return attention_mask
 
     def get_position_ids(self, seq, mask_position, device, gmask=False):
-        context_length = seq.index(self.config.bos_token_id) + 1
+        context_length = len(seq)
         if self.position_encoding_2d:
             seq_length = seq.index(self.config.bos_token_id)
             position_ids = torch.arange(context_length, dtype=torch.long, device=device)