Flight: Vancouver - Baiyun - Shanghai. Where will baggage go through customs?

I am flying in from Vancouver to Baiyun by Southern Airlines, then transfer to a domestic Southern Airlines flight to Shanghai Hongqiao 2. Do I have to claim my baggage in Baiyun to go through customs and then check it in again for the domestic flight. I have only 2 hours. Or will my baggage automatically re-route to Shanghai?