本文采用事件研究法，以中美贸易摩擦作为研究的事件对象，分析中美贸易摩擦对中国A股市场的影响。实证结果显示，在事件研究法下，中美贸易摩擦事件对A股影响显著为负（p-value < 0.0000），累计平均异常收益率为-0.18%。受此事件影响，中国A股市场总市值减少了1001.43亿元人民币。另外，本文对研究结果进行了全面的稳健性检验，通过对事件日期的调整、估计模型的调整以及相反事件的选取等方式，从不同角度验证了本文的研究结果稳健有效。本文还对在贸易摩擦中产生异常亏损的公司进行了行业分类，对公司的海外业务占比、公司规模、公司估值与异常收益率进行回归分析。研究发现，异常亏损公司所属行业与美国公布的加税清单基本一致，公司估值与异常收益率呈负相关关系，公司规模、海外业务占比与异常收益率之间并不存在显著的线性相关关系。中美两国之间日益频繁的贸易摩擦对两国乃至全球的影响已经不仅仅局限于经济领域，还扩大至政治等其他领域。由于中美贸易冲突的长期性和严峻性，研究中美贸易摩擦对预测两国贸易发展趋势有重要作用，为政府理性选择在中美经贸谈判时应采取的态度提供实证研究支持。

This paper mainly focuses on the impact of Sino-US trade friction on A share market by the event study method. The empirical results show that the Sino-US trade friction has a significantly negative impact on A share market. The cumulative average abnormal return (CAAR) is -0.18%. Affected by the event of Sino-US trade friction, the total market value of A-share market decreased by RMB 100.14 billion. In addition, comprehensive robustness tests are conducted on the research results. Through the adjustment of the date of the event, the adjustment of the estimation model and the selection of the opposite event, the results of this paper are verified to be robust and effective from different angles.The industry classification, the proportion of overseas business, valuation and size for companies that generate abnormal losses in trade friction are also analyzed in this paper. The results show that companies generating negative CAAR mainly belong to the industries in the list of additional tariffs published by US. There is a negative correlation between the company's valuation and the abnormal rate of return. There is no significant linear correlation between the company's size, the proportion of overseas business and the abnormal rate of return.The impact of the increasing trade frictions between China and the United States has not only been limited to the economic sector, but also expanded to other areas such as politics. Due to the long-term trade frictions between China and the United States, studying Sino-US trade friction plays an important role in predicting the trend of trade between the two countries, provides empirical research support for the government to rationally choose the attitude in Sino-US negotiations.