Used to be, back in the day (March 2019), that anyone could marry anyone, in terms of citizenship, in China. No more. The Civil Affairs Bureau has explicitly banned the practice of two non-Chinese citizens getting married in China as of 1 April 2019, a practice, which I recall, cost about 9rmb when I did it and resulted in this nifty little Bureaucratic Red booklet that you got to show off to your big wedding party. It screamed CHINA! If you want one of those now, you or your partner must be a Chinese citizen, according to several overseas embassies
and the official whatnot machine up in Beijing.