diff --git a/src/llmtuner/dsets/preprocess.py b/src/llmtuner/dsets/preprocess.py
index 0562d303..2a25805e 100644
--- a/src/llmtuner/dsets/preprocess.py
+++ b/src/llmtuner/dsets/preprocess.py
@@ -119,10 +119,10 @@ def preprocess_dataset(
         print("input_ids:\n{}".format(example["input_ids"]))
         print("inputs:\n{}".format(tokenizer.decode(example["input_ids"], skip_special_tokens=False)))
         print("label_ids:\n{}".format(example["labels"]))
-        print("labels:\n{}".format(
-            tokenizer.decode([d if d != IGNORE_INDEX else tokenizer.pad_token_id for d in example["labels"]],
-                             skip_special_tokens=False)
-        ))
+        print("labels:\n{}".format(''.join([
+            tokenizer.decode(d, skip_special_tokens=False)
+            if d != IGNORE_INDEX else '-100' for d in example["labels"]
+        ])))
 
     def print_pairwise_dataset_example(example):
         print("accept_ids:\n{}".format(example["accept_ids"]))