经济全球化背景下，世界各国的经济往来与联系日益密切，全球经济与世界市场日益一体化。中国与美国作为近年来GDP总量前2位的世界性经济大国，其经济政策会对自身和世界其他国家产生重要影响，同时政策的有效性也会对经济的波动产生重要的影响。本文首先汇总中美两国1998~2016年实际有效汇率的数据，分析实际有效汇率与该国国际收支、失业率、通胀指数的长期波动趋势与相关性；其次在多元回归模型的基础上，对中美两国进行模型分析，并采用平稳性检验、格兰杰因果关系检验和协整检验分析变量间的相互作用。分析结果显示，对中国而言，实际有效汇率和政府支出对GDP的影响较大；对美国而言，国际收支、失业率、货币供应量和政府支出对GDP的影响较大。美国的财政和货币政策对于GDP的影响大于中国，说明美国的政策有效性较高，本文根据此结论对增强中国政策有效性提供建议。

关键词：政策有效性、开放经济、实际有效汇率、国内生产总值

Under the background of economic globalization, the economic activities between countries have become increasingly close, and the global economy and the world market have become increasingly integrated. As the top two world economic powers, China and the U.S. will have an important impact on themselves and other countries in the world, and it is true for the effectiveness of policies. This paper first summarizes the data of the real effective exchange rate (REER) of China and the U.S. from 1998 to 2016, and analyzes the correlation between the REER and the long-term fluctuation trend of balance of payments (BOPs), unemployment rate and inflation index. Secondly, based on the multiple regression model, the stationarity test, the Granger Causality test and the cointegration test are used to analyze the interaction between these variables. The results show that for China, the REER and government spending have a greater impact on GDP; For the U.S., the BOPs, unemployment, money supply, and government spending have a greater impact on GDP. The impact of fiscal and monetary policy of the U.S. on GDP is greater than that of China, indicating that the effectiveness of U.S. policies is higher than that of China. Based on the conclusion, recommendations are made to enhance the effectiveness of China's policies.

Keywords: Policy Effectiveness, Open Economy, Real Effective Exchange Rate, Gross Domestic Product