Abstract: Recent years, many scholars focused on the social security of migrant workers, to understand the social insurance participation situation of the group. The paper selected four first tier cities in our country, making quantitative analysis of social security participation of migrant workers in these cities; we think different employment status, nature of units etc. have impacts for migrant workers’ social insurance rate. Therefore, to improve migrant workers’ social insurance rate, we should improve the quality of employment of migrant workers first, promoting them from the secondary labor market into primary labor market, promoting urbanization process in the group.