it is not like you buy one stuff here and sell it to china or vice verse. there are heavy regulations.
If a medical device wants to be sold in china, the sponosr or delegate needs to get marketing approval from China's SDA (china's FDA) by doing required clinical trials. it is a huge hurdle which is not small fish's business. After marketing approval, then you can sell it by a variety of ways. Due to heavy corruptions, one needs a lot of money to open the door to the buyers. forget about this business unless you have a well-organized, dedicated full-time team.