全球各国经济政策不确定性持续增加，我国发展面对更多逆风逆水的外部环境。全球经济政策不确定性作为外部环境因素势必会对中国经济产生深刻影响。同时，“8.11汇改”以来双向波动常态化，中国经济更容易受到汇率波动的冲击。此时，研究美国和中国经济政策不确定性对我国汇率波动的影响，对我国积极应对内外部冲击有着非常重要的意义。本文通过相关性分析方法、平稳性检验、NARDL模型方法研究美中经济政策不确定性上升和下降对人民币汇率波动的不对称效应。实证结果表明：在短期和长期内，美中经济政策不确定性的上升和下降对人民币汇率波动的影响均具有非对称性。无论是在长期还是短期内，美中经济政策不确定性的负向变动对人民币汇率波动的作用效果更为显著。

The uncertainty of economic policies in various countries around the world continues to increase, and China's development is facing more external environments facing headwinds. Global economic policy uncertainty, as an external environmental factor, is bound to have a profound impact on the Chinese economy. Meanwhile, since the "8.11 exchange rate reform", two-way fluctuations have normalized, making the Chinese economy more susceptible to the impact of exchange rate fluctuations. At this point, studying the impact of economic policy uncertainty in the United States and China on China's exchange rate fluctuations is of great significance for China to actively respond to internal and external shocks. This article uses correlation analysis methods, stationarity tests, and NARDL model methods to study the asymmetric effects of the rise and fall of economic policy uncertainty in the United States and China on the fluctuation of the RMB exchange rate. The empirical results indicate that in both the short and long term, the rise and fall of economic policy uncertainty in the United States and China have asymmetric effects on the fluctuation of the RMB exchange rate. Whether in the long or short term, the negative changes in economic policy uncertainty between the United States and China have a more significant impact on the fluctuation of the RMB exchange rate.