The concept of foreign exchange has a double meaning, that is, there are dynamic and static points. The static concept of foreign exchange is divided into narrow foreign exchange concept and broad foreign exchange concept. In a narrow sense, foreign exchange refers to various means of payment expressed in foreign currency, which are generally accepted by all countries and can be used for international settlement of creditor's rights and debts. It must have three characteristics: affordability (assets that must be expressed in foreign currency), availability (claims that can be compensated abroad) and convertibility (foreign currency assets that can be freely converted into other means of payment). Foreign exchange in a broad sense refers to all assets owned by a country in foreign currency. The International Monetary Fund (IMF) defines this as: "Foreign exchange is the creditor's rights held by monetary management authorities (central bank, monetary management institutions, foreign exchange stabilization fund and the Ministry of Finance) in the form of bank deposits, treasury bonds and long-term and short-term government securities. It can be used when there is a deficit in the balance of payments. " China's 1997 revised and promulgated Regulations on Foreign Exchange Management stipulates: "Foreign exchange refers to the following means of payment and assets expressed in foreign currency that can be used for international settlement:

Foreign currency, including coins, paper money, etc. ;

Foreign currency payment vouchers, including bills, bank deposit vouchers and postal savings vouchers. ;

Foreign currency securities, including government bonds, government bonds, corporate bonds, stocks, coupons, etc. ;

Special drawing rights and European currency units;

5. Other foreign exchange assets. The dynamic concept of foreign exchange refers to the flow of money between countries and a specialized commercial activity of exchanging one country's currency for another to pay off international creditor's rights and debts. It is the abbreviation of foreign exchange.