Solved by xieydd in post #10 
              
              
                I think somebody have the same error: Issue with Quantization 
I think i know the answew: 
# pytorch 1.4
#save
torch.save(net.state_dict(),'xx') # fp32 model
#load
model.qconfig = torch.quantization.get_default_qat_qconfig("fbgemm")
model.fuse_model()
torch.quantization.prepare_qat(net, inplace=True…