Since its birth, RMB has always been a non-convertible currency, and its price is determined by the People's Bank of China, the central bank, only as a policy means to regulate import and export trade and improve the balance of payments. The quotation of RMB is roughly divided into two stages, namely, the exchange rate before the reform and opening up and the exchange rate after the reform and opening up. 1978 before the reform and opening up, 1949- 1952 during the period of national economic recovery, the RMB quotation was not based on gold, and the management floating system was implemented, and the price was the basis for determining the exchange rate; From March 1 955 to March19710/0, the Bretton Woods system was in a stable period, and the RMB exchange rate remained at 2.46 18 yuan (1USD exchange) for nearly 1 6 years. From 1973 to 1979, the RMB exchange rate has only been adjusted several times. By 1978, the central parity of RMB against the US dollar is 1.684 yuan (1 US dollar) [1]. After the reform and opening-up, the RMB exchange rate has gone through the dual-track stage of listing price and swap price, the flexible peg to the US dollar after the merger of exchange rates, the rigid peg to the US dollar after the Asian financial crisis, and the exchange rate system reform of 2 1 on July 2005. The dual-track exchange rate system from 1979 to 1994 is the period with the largest depreciation of RMB, from 1979 to10/9 yuan (annual average price). In the period of dual-track exchange rate system, it still exists in foreign exchange certificates, and its face value is equivalent to RMB on the surface. During this period, there was a black market in foreign exchange, which was banned by the government. At first, foreign exchange certificates were mainly fried, and then foreign currency was directly fried. The black market price of foreign exchange (foreign exchange certificates and foreign currencies) is much higher than the official exchange rate, and the highest difference in the previous period is nearly double, and then it gradually falls back until it is close to the official listing price; After entering 1990, the over-the-counter (black market) foreign exchange price became weaker than the official listing price, and the foreign exchange certificates gradually faded out of the market. From 1994 to the exchange rate reform in 2005, the RMB kept above 8.27 yuan against the US dollar (1 US dollar). After the exchange rate reform in 2005, the RMB gradually entered the stage of appreciation. The RMB rose from 8.2765 yuan (1 USD) before the exchange rate reform to 7.3046 yuan [2] at the end of 2007, with an appreciation rate of 1 1.74%.