"Exchange rate", also known as "foreign exchange market" or "exchange rate", is the ratio of one country's currency to another, and the price of another currency is expressed in one currency. Because of the different names and values of currencies in the world, one country's currency should set an exchange rate for other countries' currencies, that is, the exchange rate. Exchange rate is also a financial means for a country to achieve its political goals. The exchange rate will change because of interest rates, inflation, national politics and national economies. The reason why currencies of different countries can be compared with each other and form a price relationship is because they all represent a certain amount of value, which is the basis for determining the exchange rate. Exchange rates are usually expressed in two ways, namely, local currency exchange rate and foreign currency exchange rate. The exchange rate of local currency and foreign currency are two relative concepts, and their ups and downs have just opposite economic phenomena.