The 2015 China Comprehensive Social Survey data (CGSS) was used to compare the differences between floating population and unfloating population, rural-urban floating population and urban floating population, and the propensity score matching method (PSM) was used to estimate the impact of mobility and different types of mobility on their social security participation. The study found that mobility has a negative impact on social security participation is significant. Compared with the unmobile people, the probability of migrant people participating in social security is lower, with a decrease of about 9%; the probability of participation in social security is lower than that of urban-urban floating population, with a decrease of about 12%.