China government has opened foreign exchange control in 2007, and individuals can freely buy and sell 17 kinds of foreign currency listed in domestic large, medium and small commercial banks with the equivalent of less than 50,000 US dollars (less than 50,000 US dollars per person per year) with their valid identity documents.

That is to say, when you travel abroad and return to China, you can go to the bank to fill out a foreign exchange settlement (sale)/purchase (purchase) form with your personal ID card and buy and sell foreign currency at the bank counter.

The types of convertible foreign currencies are: US Federal Reserve, Japanese paper money, British pound paper money, EU dollar, Canadian dollar, Australian dollar, Korean won, China dollar, China pataca, etc. There is a detailed list and a big screen in the bank.