Abstract: The paper pays attention to the reform and perfection of the social security of migrant labors from the perspective of migration of migrant labors. First, the paper analyzes the new characteristics of the present stage of the migrant labors migration, and then states social security status of migrant labors, that is highly fragmented system, low coverage and security level. Based on this, the paper analyses the effect on the migration of migrant labors of the social insurance including medical insurance, social assistance, social welfare and the status of social insurance join. At last,the paper puts forward some thoughts on the construction of social security system of migrant labors