Abstract: In recent years, the gap of social security levels between provinces in China has been gradually narrowed, and the social security levels of local governments have the characteristics of spatial agglomeration. By constructing a spatial Durbin model of local governments’ social security levels with a weight matrix of spatial adjacent, geographical distance and economic distance, this paper empirically tests the convergence of inter-regional social security level and the convergence mechanism. The results show that the convergence speed of the expenditure level of inter-regional social insurance fund is greater than that of the expenditure level of the fiscal social insurance. Population mobility has a promoting effect on the convergence of the inter-regional social security level, while the fiscal decentralization would slow the speed of convergence. In addition, the narrowing of the gaps between the inter-regional economic levels and between the fiscal capacity levels is also the reason for the convergence of social security level. Therefore, it is recommended to promote and perfect the transfer and continuation system of social insurance, to improve the overall planning levels of social insurance system, to narrow the gap of the inter-regional urbanization levels, and to establish a special transfer payment system for social security.

Key words: social security level; population mobility; fiscal decentralization; spatial convergence