After the 19th national congress put forward the “two pillar regulatory framework”，the guiding opinions on improving the supervision of systemically important financial institutions proposed to strengthen macro prudential supervision，defined the definition and scope of systemically important financial institutions，and stipulated the evaluation process and overall method. Combined with the regulatory requirements of documents，this report establishes the evaluation system and calculation method of the systematic importance of securities companies from the aspects of the scale，relevance，substitutability，complexity and asset realization of securities institutions，and ranks and analyzes the systematic importance of securities companies. The research shows that the total assets of the top 20 securities companies account for 72.45% of the total assets of the whole industry，which does not meet the regulatory requirements of 75%，which indicates that the securities industry is far from “big but not collapsed”. In the future，the regulatory authorities may promote the merger and reorganization in the industry to improve the systemic importance of the head institutions of the securities industry. In addition to the size of institutions，the relevance and complexity among securities institutions are also very important. They should be incorporated into China’s macro prudential supervision system and serve as the specific content of the macro prudential supervision framework of the securities market. For the supervision of systemically important securities institutions，in accordance with the principle of macro prudential supervision，we should clarify the evaluation methods and scope，clarify the responsibilities of regulatory departments，establish a risk monitoring and handling mechanism for systemically important securities institutions，effectively combine micro Prudential and macro prudential supervision to prevent systemic risks.