diff --git a/paddlespeech/s2t/exps/u2/model.py b/paddlespeech/s2t/exps/u2/model.py
index 5b7654d4..95cb47f5 100644
--- a/paddlespeech/s2t/exps/u2/model.py
+++ b/paddlespeech/s2t/exps/u2/model.py
@@ -23,6 +23,7 @@ import jsonlines
 import numpy as np
 import paddle
 from paddle import distributed as dist
+from paddle.nn.utils import clip_grad_norm_
 
 from paddlespeech.s2t.frontend.featurizer import TextFeaturizer
 from paddlespeech.s2t.io.dataloader import DataLoaderFactory
@@ -47,14 +48,16 @@ class U2Trainer(Trainer):
     def __init__(self, config, args):
         super().__init__(config, args)
 
-    def train_batch(self, batch_index, batch_data, msg):
+    def train_batch(self, batch_index, batch_data, scaler, msg):
         train_conf = self.config
         start = time.time()
 
         # forward
         utt, audio, audio_len, text, text_len = batch_data
-        loss, attention_loss, ctc_loss = self.model(audio, audio_len, text,
-                                                    text_len)
+        with paddle.amp.auto_cast(
+                level=self.amp_level, enable=True if scaler else False):
+            loss, attention_loss, ctc_loss = self.model(audio, audio_len, text,
+                                                        text_len)
 
         # loss div by `batch_size * accum_grad`
         loss /= train_conf.accum_grad
@@ -77,12 +80,24 @@ class U2Trainer(Trainer):
             # processes.
             context = nullcontext
         with context():
-            loss.backward()
+            if scaler:
+                scaler.scale(loss).backward()
+            else:
+                loss.backward()
             layer_tools.print_grads(self.model, print_func=None)
 
         # optimizer step
         if (batch_index + 1) % train_conf.accum_grad == 0:
-            self.optimizer.step()
+            # do global grad clip
+            if train_conf.global_grad_clip != 0:
+                # need paddlepaddle==develop or paddlepaddle>=2.5
+                clip_grad_norm_(self.model.parameters(),
+                                train_conf.global_grad_clip)
+            if scaler:
+                scaler.step(self.optimizer)
+                scaler.update()
+            else:
+                self.optimizer.step()
             self.optimizer.clear_grad()
             self.lr_scheduler.step()
             self.iteration += 1
@@ -173,7 +188,8 @@ class U2Trainer(Trainer):
                             report("epoch", self.epoch)
                             report('step', self.iteration)
                             report("lr", self.lr_scheduler())
-                            self.train_batch(batch_index, batch, msg)
+                            self.train_batch(batch_index, batch, self.scaler,
+                                             msg)
                             self.after_train_batch()
                             report('iter', batch_index + 1)
                             if not self.use_streamdata:
@@ -253,6 +269,19 @@ class U2Trainer(Trainer):
                 model_conf.output_dim = self.test_loader.vocab_size
 
         model = U2Model.from_config(model_conf)
+
+        # For Mixed Precision Training
+        self.use_amp = self.config.get("use_amp", True)
+        self.amp_level = self.config.get("amp_level", "O1")
+        if self.train and self.use_amp:
+            self.scaler = paddle.amp.GradScaler(
+                init_loss_scaling=self.config.get(
+                    "scale_loss", 32768.0))  #amp default num 32768.0
+            #Set amp_level
+            if self.amp_level == 'O2':
+                model = paddle.amp.decorate(models=model, level=self.amp_level)
+        else:
+            self.scaler = None
         if self.parallel:
             model = paddle.DataParallel(model)
 
@@ -290,7 +319,6 @@ class U2Trainer(Trainer):
             scheduler_type = train_config.scheduler
             scheduler_conf = train_config.scheduler_conf
             return {
-                "grad_clip": train_config.global_grad_clip,
                 "weight_decay": optim_conf.weight_decay,
                 "learning_rate": lr_scheduler
                 if lr_scheduler else optim_conf.lr,
diff --git a/paddlespeech/s2t/training/trainer.py b/paddlespeech/s2t/training/trainer.py
index 4a69d78a..53a5d03f 100644
--- a/paddlespeech/s2t/training/trainer.py
+++ b/paddlespeech/s2t/training/trainer.py
@@ -110,6 +110,7 @@ class Trainer():
         self.rank = dist.get_rank()
         self.world_size = dist.get_world_size()
         self._train = True
+        self.scaler = None
 
         # print deps version
         all_version()
@@ -187,7 +188,8 @@ class Trainer():
         infos.update({
             "step": self.iteration,
             "epoch": self.epoch,
-            "lr": self.optimizer.get_lr()
+            "lr": self.optimizer.get_lr(),
+            "scaler": self.scaler
         })
         self.checkpoint.save_parameters(self.checkpoint_dir, self.iteration
                                         if tag is None else tag, self.model,
@@ -211,6 +213,8 @@ class Trainer():
             # lr will resotre from optimizer ckpt
             self.iteration = infos["step"]
             self.epoch = infos["epoch"]
+            self.scaler = paddle.amp.GradScaler()
+            self.scaler.load_state_dict(infos["scaler"])
             scratch = False
             logger.info(
                 f"Restore ckpt: epoch {self.epoch }, step {self.iteration}!")