Social security system in China is progressive formation.Its historical background and real-world conditions determine the pattern of the fragmentation of the existing social security system.The future development of China's social security system should start with the fragmentation to be integrated.The integration of the social security system should adhere to several principles such as unified planning，the baseline equality and sustainability.To promote the integration of the social security system，we should focus on improving the social security management system and realizing effective convergence of the social security system between urban and rural areas，regions and groups.At the same time，we should try to decentralize social security programs，improve the level of social security co-ordination and give a reasonable division of duties and powers of the government on social security.