Exchange rate is the most important comprehensive price index used in international economy transaction and executes the function of transforming price . so it becomes the most important lever of regulating trade balance . therefore many countries take exchange rate as an adjustment instrument in order to regulate trade balance 汇率是一个国家进行国际经济活动时最重要的综合性价格指标，在国际金融和国际贸易活动中执行着价格转换职能，从而成为调节一国贸易收支的重要杠杆，它的变动对一国对外贸易的平衡与国内经济活动的波动都具有深刻的影响。
