diff --git a/applications/ColossalChat/coati/trainer/prm.py b/applications/ColossalChat/coati/trainer/prm.py
index 73fdb6c5e..3c916c308 100644
--- a/applications/ColossalChat/coati/trainer/prm.py
+++ b/applications/ColossalChat/coati/trainer/prm.py
@@ -82,7 +82,7 @@ class ProcessRewardModelTrainer(SLTrainer):
 
                 self.wandb_run = wandb.init(project="Coati-PRM", sync_tensorboard=True)
 
-    def _train(self, epoch):
+    def _train(self, epoch: int):
         self.model.train()
         step_bar = tqdm.trange(
             len(self.train_dataloader) // self.accumulation_steps,
@@ -129,6 +129,31 @@ class ProcessRewardModelTrainer(SLTrainer):
                     f"Saved checkpoint at epoch {epoch} step {self.num_train_step} at folder {self.save_dir}"
                 )
 
-    def _eval(epoch: int):
-        # TODO
-        pass
+    def _eval(self, epoch: int):
+        self.model.eval()
+
+        step_bar = tqdm.trange(
+            len(self.eval_dataloader),
+            desc=f"Epoch {epoch + 1}/{self.max_epochs}",
+            disable=not is_rank_0(),
+        )
+        for batch in self.eval_dataloader:
+            batch = to_device(batch, self.device)
+            logits = self.model(batch["input_ids"])["logits"]
+            loss = self.loss_fn(batch["labels"], logits)
+            loss_mean = all_reduce_mean(tensor=loss)
+            self.accumulative_meter.add(
+                "loss", loss_mean.to(torch.float16).item(), count_update=batch["input_ids"].size(0)
+            )
+            step_bar.update()
+
+        loss_mean = self.accumulative_meter.get("loss")
+        msg = "Evaluation Result:\n"
+        for tag in ["loss"]:
+            msg = msg + f"{tag}: {self.accumulative_meter.get(tag)}\n"
+        self.coordinator.print_on_master(msg)
+        if self.save_dir is not None:
+            os.makedirs(self.save_dir, exist_ok=True)
+            with open(os.path.join(self.save_dir, f"eval_result_epoch{epoch}.txt"), "w") as f:
+                f.write(msg)
+        step_bar.close()