diff --git a/applications/ColossalChat/coati/trainer/kto.py b/applications/ColossalChat/coati/trainer/kto.py
index f87bf53c40cf..9a2322a050d4 100755
--- a/applications/ColossalChat/coati/trainer/kto.py
+++ b/applications/ColossalChat/coati/trainer/kto.py
@@ -273,11 +273,11 @@ def _eval(self, epoch: int):
         self.model.eval()
         self.accumulative_meter.reset()
         step_bar = trange(
-            len(self.train_dataloader) // self.accumulation_steps,
+            len(self.eval_dataloader) // self.accumulation_steps,
             desc=f"Epoch {epoch + 1}/{self.max_epochs}",
             disable=not is_rank_0(),
         )
-        for i, batch in enumerate(self.train_dataloader):
+        for i, batch in enumerate(self.eval_dataloader):
             batch = to_device(batch, self.device)
             (input_ids, attention_mask, loss_mask, label, kl_input_ids, kl_attention_mask, kl_loss_mask) = (
                 batch["input_ids"],