Abstract: Based on the statistical data of 1995-2006 in China,the paper aims to carry out theoretical analysis and empirical analysis about the causal relationship between rural labor mobility and urban-rural income disparity.It finds that rural labor mobility and urban–rural income disparity reciprocally affect each other.Meanwhile there is a bilateral Granger causal relationship between rural labor mobility and urban-rural income disparity.Therefore,in order to reduce urban-rural income disparity,we should on one hand improve rural labor mobility,and on the other hand, in order to further promote the rural labor mobility,we must proceed from two aspects：increase the marginal utility of non-agricultural income and reduce its cost.