diff --git a/ppdet/engine/trainer.py b/ppdet/engine/trainer.py
index b8d3b2aca6246cdd16d78b5b63b1f0836407d8f5..360a71efc340734e2534377a6d37d81ad1e47a37 100644
--- a/ppdet/engine/trainer.py
+++ b/ppdet/engine/trainer.py
@@ -34,7 +34,6 @@ from paddle.static import InputSpec
 from ppdet.optimizer import ModelEMA
 
 from ppdet.core.workspace import create
-from ppdet.modeling.architectures.meta_arch import BaseArch
 from ppdet.utils.checkpoint import load_weight, load_pretrain_weight
 from ppdet.utils.visualizer import visualize_results, save_result
 from ppdet.metrics import Metric, COCOMetric, VOCMetric, WiderFaceMetric, get_infer_results, KeyPointTopDownCOCOEval, KeyPointTopDownMPIIEval
@@ -346,10 +345,11 @@ class Trainer(object):
         assert self.mode == 'train', "Model not in 'train' mode"
         Init_mark = False
 
-        sync_bn = (getattr(self.cfg, 'norm_type', None) in [None, 'sync_bn'] and
+        sync_bn = (getattr(self.cfg, 'norm_type', None) == 'sync_bn' and
                    self.cfg.use_gpu and self._nranks > 1)
         if sync_bn:
-            self.model = BaseArch.convert_sync_batchnorm(self.model)
+            self.model = paddle.nn.SyncBatchNorm.convert_sync_batchnorm(
+                self.model)
 
         model = self.model
         if self.cfg.get('fleet', False):
diff --git a/ppdet/modeling/architectures/meta_arch.py b/ppdet/modeling/architectures/meta_arch.py
index 770f1fd19ff66a44245460ffe22958dec767b6cd..d01c34735653050c7b78799f06cbf72b85979a61 100644
--- a/ppdet/modeling/architectures/meta_arch.py
+++ b/ppdet/modeling/architectures/meta_arch.py
@@ -70,7 +70,7 @@ class BaseArch(nn.Layer):
                 outs.append(self.get_pred())
 
             # multi-scale test
-            if len(outs) > 1:
+            if len(outs)>1:
                 out = self.merge_multi_scale_predictions(outs)
             else:
                 out = outs[0]
@@ -87,9 +87,7 @@ class BaseArch(nn.Layer):
             keep_top_k = self.bbox_post_process.nms.keep_top_k
             nms_threshold = self.bbox_post_process.nms.nms_threshold
         else:
-            raise Exception(
-                "Multi scale test only supports CascadeRCNN, FasterRCNN and MaskRCNN for now"
-            )
+            raise Exception("Multi scale test only supports CascadeRCNN, FasterRCNN and MaskRCNN for now")
 
         final_boxes = []
         all_scale_outs = paddle.concat([o['bbox'] for o in outs]).numpy()
@@ -98,11 +96,9 @@ class BaseArch(nn.Layer):
             if np.count_nonzero(idxs) == 0:
                 continue
             r = nms(all_scale_outs[idxs, 1:], nms_threshold)
-            final_boxes.append(
-                np.concatenate([np.full((r.shape[0], 1), c), r], 1))
+            final_boxes.append(np.concatenate([np.full((r.shape[0], 1), c), r], 1))
         out = np.concatenate(final_boxes)
-        out = np.concatenate(sorted(
-            out, key=lambda e: e[1])[-keep_top_k:]).reshape((-1, 6))
+        out = np.concatenate(sorted(out, key=lambda e: e[1])[-keep_top_k:]).reshape((-1, 6))
         out = {
             'bbox': paddle.to_tensor(out),
             'bbox_num': paddle.to_tensor(np.array([out.shape[0], ]))
@@ -124,16 +120,3 @@ class BaseArch(nn.Layer):
 
     def get_pred(self, ):
         raise NotImplementedError("Should implement get_pred method!")
-
-    @classmethod
-    def convert_sync_batchnorm(cls, layer):
-        layer_output = layer
-        if getattr(layer, 'norm_type', None) == 'sync_bn':
-            layer_output = nn.SyncBatchNorm.convert_sync_batchnorm(layer)
-        else:
-            for name, sublayer in layer.named_children():
-                layer_output.add_sublayer(name,
-                                          cls.convert_sync_batchnorm(sublayer))
-
-        del layer
-        return layer_output
diff --git a/ppdet/modeling/backbones/esnet.py b/ppdet/modeling/backbones/esnet.py
index 86c28655d1a763db14bc4b9b2d83af7b5000fb27..2b3f3c54a2f3bbc50caba2a86dd82b96bf689ba4 100644
--- a/ppdet/modeling/backbones/esnet.py
+++ b/ppdet/modeling/backbones/esnet.py
@@ -20,7 +20,7 @@ import paddle
 import paddle.nn as nn
 import paddle.nn.functional as F
 from paddle import ParamAttr
-from paddle.nn import Conv2D, MaxPool2D, AdaptiveAvgPool2D
+from paddle.nn import Conv2D, MaxPool2D, AdaptiveAvgPool2D, BatchNorm
 from paddle.nn.initializer import KaimingNormal
 from paddle.regularizer import L2Decay