Abstract: China has established the world's largest social security system since it launched its Reform and Opening-up program 40 years ago. Over the course of the reform, the function of social security system has significantly transformed from a supporting project for economic reform to the institutional basis of modern national governance. Yet, China's social security system is not strong enough to meet the demands of modernizing national governance system and ability. In the future, China needs to improve the quality of social security, for which more work needs to be done in terms of policy-making, institutionalization, openness, flexibility and centralization of management.