The best one is Hua Xia Bank’s bank card, which charges no handling fee for withdrawing money, and few people know about it. Bank of China, China Construction Bank, and Bank of China charge a handling fee of about 100~200B every time you withdraw money, and the limit for each withdrawal is about 20000~25000B.

I think it is not worthwhile to convert it into U.S. dollars in China. First of all, you will lose money after you convert RMB into U.S. dollars. So I don't recommend it. In fact, it is more cost-effective to exchange it at home, and the exchange rate is a little lower than the black market in Bangkok.

If you want to change in Bangkok, there is a super rich store near the central word where you can change. Remember to bring your passport. Super Rich is a legal and safe currency exchange agency, so don’t worry~~

If the bank card has the UnionPay logo, you can withdraw money from ATMs in Thailand. The handling fee is as above~