diff --git a/scripts/cal_ppl.py b/scripts/cal_ppl.py
index bdfc210b..6c8c6174 100644
--- a/scripts/cal_ppl.py
+++ b/scripts/cal_ppl.py
@@ -1,6 +1,6 @@
 # coding=utf-8
-# Calculates the ppl of pre-trained models.
-# Usage: python cal_flops.py --model_name_or_path path_to_model --batch_size 1 --seq_length 512
+# Calculates the ppl on the dataset of the pre-trained models.
+# Usage: python cal_ppl.py --model_name_or_path path_to_model --save_name ppl.json
 
 import json
 from typing import Dict
@@ -19,6 +19,7 @@ from llmtuner.model import load_model, load_tokenizer
 
 def cal_ppl(
     model_name_or_path: str,
+    save_name: str,
     batch_size: int = 4,
     stage: str = "sft",
     dataset: str = "alpaca_en",
@@ -69,10 +70,10 @@ def cal_ppl(
             sentence_logps = (token_logps * loss_mask).sum(-1) / loss_mask.sum(-1)
             perplexities.extend(sentence_logps.exp().tolist())
 
-    with open("ppl.json", "w", encoding="utf-8") as f:
+    with open(save_name, "w", encoding="utf-8") as f:
         json.dump(perplexities, f, indent=2)
 
-    print("Perplexities have been saved at ppl.json.")
+    print("Perplexities have been saved at {}.".format(save_name))
 
 
 if __name__ == "__main__":