Reply to myself: I found that if the pretrained network changes from nn.Sequential to nn.ModuleList, and the code changes below:
for k, m in enumerate(Net):
                if type(m).__name__ == 'BatchNorm2d': 
                    planes = m.num_features 
                    eps = m.eps 
                    momentum = m.momentum 
                    affine = m.affine

                   Net[k] = SynchronizedBatchNorm2d(planes, eps, momentum, affine) 
                    # init parameters 
                    Net[k].running_mean = m.running_mean 
                   Net[k].running_var = m.running_var 
                    if affine: 
                        Net[k].weight = m.weight 
                        Net[k].bias = m.bias  

it will works fine for me.  But i am wondering if there is some solution for network of type nn.Sequential