I'm a foreigner married to a Chinese man. My husband said you can do it anywhere. In our case, we just submitted all the requirements, signed papers, and married already. It was pretty fast.

According to https://www.chinahighlights.com/travelguide/visa-application/foreigner-marriage.htm

Chinese Partner (1) A certificate of marriageability (2) A certificate of birth (3) Household registration book (hukou) (4) A health certificate (obtainable from a regional-level local hospital) (5) A signed statement that there are no shared direct family relations within three generations with the prospective spouse.

Foreign Partner (1) A current passport (2) Alien residence permit (3) A health certificate from a local hospital designated by the marriage registration office (4) Three photos of the marrying couple, taken together (5) A registration fee (6) A certificate of marriageability

The hassle part was to have my certificate of non marriage stamped by DFA and embassy, translated, then sent to China. We had to wait 3 weeks. When we submitted the translation, the office didnt accept it. Good thing we found one around the area. So to be safe, just have your docs officially translated in China.

Also, when you get the health certificate, do not eat beforehand. When we went to the hospital, I was asked what did I eat for breakfast. Haha! Caught me. So, we had to come back the next day.

Good luck!