M & A can optimize the market structure of the securities industry and enable securities companies to allocate resources more effectively. From the development of China’s securities market，M & A in China’s securities industry has experienced three waves. At present，China’s securities industry is in the third wave of M & A. The purpose of M & A is mainly to improve market competitiveness through business complementarity，regional integration or overseas M & A. From the development of securities companies in recent years，there are some problems in M & A，focusing on financial risks and integration in the process of M & A，including financial integration，human resources integration，corporate culture integration and so on. In the comparison of the U.S. securities industry，it is found that China’s securities companies still need to adjust their business structure through M & A integration. The integration between head securities companies is conducive to building aircraft carrier securities companies in China. Securities companies should determine their market positioning according to their own advantages，provide differentiated services and realize differentiated competitive advantages. With the acceleration of China’s financial opening to the outside world，the restriction on the proportion of foreign shares of securities companies has been lifted，and foreign investment has accelerated the layout of China’s capital market. From the perspective of policy，the regulatory authorities encourage China’s securities companies to achieve rapid development in terms of capital strength，management level and information technology，and encourage strong countries to jointly build an international first-class investment bank.