The direct cause of the plunge is the Fed's further withdrawal from quantitative easing. In addition, it is also related to the continued weak economic situation in China since the beginning of this year. This round of RMB depreciation will also have a lasting impact on the prices of RMB-denominated assets such as commodities, real estate market and even stock market represented by industrial products. This devaluation of RMB changed the market's expectation of unilateral appreciation of RMB.