Abstract Exchange rate has been a long term issue in economics, but until today, economics theory still cannot explain how the exchange rate level is determined and what makes exchange rate change. Of course, the economy explanations of exchange rate are very important, but one state’s exchange rate, especially big power’s exchange rate is determined by the interaction of a variety of political and economic factors. The issue of exchange rate is never an economy issue, is a political economy issue. In this paper, I am going to study the Plaza Accord in 1985 and 2005 RMB exchange rate reform with international political economy theory, constitute power and international monetary theory. This paper demonstrates that because the United States is powerful in the four structural powers and in the relations of international monetary power than China and Japan, this make the United States can put pressure on these two countries and China and Japan cannot say no to United States’ requires. But China is not ally of the United States, it does not depends on United States in security structure. And United States’ power is not unlimited, with the expansion of current account deficit and confident reduction of market factors to United States, these conditions makes China’s reform can be progressive. Key words: RMB exchange rate, International Political Economy, Constitute Power, International Monetary Power