The exchange rate of US dollars refers to the exchange rate or price at which US dollars can be converted into RMB, that is, the exchange rate between two currencies, and can also be regarded as the value of one country's currency against another country's currency. The conversion formula between USD and RMB is USD = RMB × RMB-USD exchange rate.

After the People's Bank of China closes every working day, the closing price of USD against RMB in the inter-bank foreign exchange market on that day will be the middle price of USD against RMB on the next working day. Commercial banks set their own median price according to the median price announced by the People's Bank of China, and then float a certain number of points up and down on the basis of the median price according to the situation of banks to get the buying price and selling price.