How to exchange foreign currencies for RMB? 
(I) Overseas visitors to China can exchange foreign currencies for RMB cash in advance in relevant countries or regions before bringing it into China (each visitor is allowed to take up to RMB20,000 in cash in or out of the country).
(II) Overseas visitors to China can exchange foreign currencies for RMB cash at commercial bank branches, money changers, and self-service currency exchange machines at international airports, land ports, ports, and other entry ports, or withdraw RMB cash using international bank cards at ATMs.

Updated on March 13, 2024

Source: A Guide to Working and Living in China as Business Expatriates (2024 Edition)