Abstract: Through an analysis of the data from the China Enterprise-Labor Matching Survey Data (CEES), this paper measures the influencing factors of social security investment on the Total Factor Productivity from the perspectives of enterprise social security coverage, kinds and quantity of social security, and per capita social security expenditure, so as to provide enlightenment for the manufacturing enterprises to increase employee work enthusiasm, reduce the excessive mobility of the labor force, and improve their TFP in the context of present macro economic development. The findings of OLS regression show that the social security investment of enterprises has a significant positive effect on their total factor productivity. Through the mediating effect it is further discovered that high quality human capital structure and management level are the important channel, through which the social security investment can act on the productivity. Meanwhile, when the social security collection is turned to imposition by the tax authorities, enterprises should regard their social security investment as a kind of effective human capital investment and incentive measure, through a reasonable social security investment portfolio the productivity can be increased, so as to achieve a reasonable management of the corporate human resource structure and labor costs.

Key words: social security investment of enterprises; social security coverage; human capital; Total Factor Productivity