The establishment and improvement of social assistance system in line with China's economic and social development, safeguarding the interests of social vulnerable groups, ensuring people's survival, education, development and other aspects of the starting point of fairness, is conducive to promoting social justice and achieving social harmony. Taking city a as an example, this paper only puts forward some views and suggestions on the relevant system and policy implementation problems faced by the social assistance subsystem in the social security system, hoping that the relevant departments will pay attention to the coordination and integration of social policies.