一、引言自2005年7月21日中国央行宣布人民币放弃盯住美元的固定联系汇率,实行有管理的浮动汇率,到2008年6月三年时间共计升值20%。即美元与人民币比价由1:8.27变成1:6.82。国际金融危机爆发后,为应对危机保增长,2008年7月人民币止升反跌,出现了三年升值中 I. Introduction Since July 21, 2005, the People’s Bank of China announced renminbi renounced the fixed-linked exchange rate pegged to the U.S. dollar and implemented a managed floating exchange rate that has appreciated by 20% in the three years to June 2008. That is, the ratio of the U.S. dollar to the Chinese yuan has changed from 1: 8.27 to 1: 6.82. After the outbreak of the international financial crisis, in response to the crisis, the renminbi rose steadily in July 2008 and rose in value for three years