Overseas mergers and acquisitions (hereafter called M&A) by Chinese enterprises are an important component of outer circulation under the dual cycle strategy, which not only actively layouts for international circulation, but also introduces advanced technology, expands overseas markets, and ensures the supply of raw materials for domestic circulation. This paper studies the short-term and long-term performance of overseas mergers and acquisitions of Chinese A-share listed companies from 2014 to 2018 by using the event study method, cumulative average excess return and accounting indicator method, and combining with China overseas Investment National Risk Rating System (CROIC-IWEP). The study finds that country risk, political risk, economic risk and financial risk all have a negative effect on the overseas M&A performance of Chinese enterprises, and political risk' negative effect is most obvious. A good relationship with China can have a positive effect on the overseas M&A performance, among which the countries or regions with the second-best relationship with China have the most significant impact on the abnormal return rate after M&A. Further research shows that enterprises can increase the success rate of M&A through their overseas subsidiaries. Meanwhile, financial institutions and intermediaries can alleviate the information asymmetry between acquirer and its target firm in the process of M&A, which is helpful to improve the success rate and scale of M&A. Therefore, some countermeasures and suggestions are put forward, such as establishing national risk identification, early warning and control mechanism, establishing overseas investment risk sharing mechanism, and constructing economic community.