Kld
If you have a US FAA ATPL you will only be able to fly their N registered fleet. To fly the B registered fleet (chinese registered) you need to pass a CAAC medical, the CAAC ATPL written exam, and a checkride with CAAC examiner. Unfortunately there is no easy straiht forward application form to fill out to get a CAAC ATPL conversion.
Cheers
MYH