Based on the CGSS（Chinese General Social Survey） database and using the Difference?in?Differences （DID） method， this paper examines the differential impact of the free compulsory education as an exogenous policy variable on the gap between urban and rural human capital accumulation. The results shows that the free compulsory education policy can significantly reduce the gap between urban and rural individuals in terms of schooling years， cognitive ability and health， but it fails to narrow the gap between urban and rural individuals in non?cognitive ability， which remains valid after a number of tests. Heterogeneity analysis shows that the policy exerts its most positive effect in the middle social status households and the central regions in China.