When I swiped my credit card abroad and left UnionPay, why didn't I get RMB instead of US dollars?

First of all, your credit card must be a dual-currency card instead of a single-currency card, that is, you can spend both RMB and US dollars in the card. Therefore, when you spend money abroad, you will automatically take the dollar bill with you. After that, you can deposit it in RMB, use RMB to purchase foreign exchange for repayment, or directly deposit it in US dollars for repayment.