diff --git a/ppdet/engine/trainer.py b/ppdet/engine/trainer.py
index 321c4d17deabe77d6f72a70a87b17f0956a45779..4dba75724cf2484dcc4efa2265cfe34b1db184a8 100644
--- a/ppdet/engine/trainer.py
+++ b/ppdet/engine/trainer.py
@@ -362,8 +362,8 @@ class Trainer(object):
             model = paddle.DataParallel(
                 self.model, find_unused_parameters=find_unused_parameters)
 
-        # initial fp16
-        if self.cfg.get('fp16', False):
+        # enabel auto mixed precision mode
+        if self.cfg.get('amp', False):
             scaler = amp.GradScaler(
                 enable=self.cfg.use_gpu, init_loss_scaling=1024)
 
@@ -401,7 +401,7 @@ class Trainer(object):
                 self._compose_callback.on_step_begin(self.status)
                 data['epoch_id'] = epoch_id
 
-                if self.cfg.get('fp16', False):
+                if self.cfg.get('amp', False):
                     with amp.auto_cast(enable=self.cfg.use_gpu):
                         # model forward
                         outputs = model(data)
diff --git a/tools/train.py b/tools/train.py
index 088a41793189603cbe5f74d02c0f323a5fde70c0..ddbf24fdaadaff781c4cd57a0df40bf1d3340c97 100755
--- a/tools/train.py
+++ b/tools/train.py
@@ -60,10 +60,10 @@ def parse_args():
         help="If set True, enable continuous evaluation job."
         "This flag is only used for internal test.")
     parser.add_argument(
-        "--fp16",
+        "--amp",
         action='store_true',
         default=False,
-        help="Enable mixed precision training.")
+        help="Enable auto mixed precision training.")
     parser.add_argument(
         "--fleet", action='store_true', default=False, help="Use fleet or not")
     parser.add_argument(
@@ -130,7 +130,7 @@ def run(FLAGS, cfg):
 def main():
     FLAGS = parse_args()
     cfg = load_config(FLAGS.config)
-    cfg['fp16'] = FLAGS.fp16
+    cfg['amp'] = FLAGS.amp
     cfg['fleet'] = FLAGS.fleet
     cfg['use_vdl'] = FLAGS.use_vdl
     cfg['vdl_log_dir'] = FLAGS.vdl_log_dir