Through the analysis of the spatial effect on the real estate market, this paper builds the spatial lag model and spatial error model, and assesses the effect of urban rail traffic on the value of residential along. Taking Line 2 of Changsha Metro as an example, and using MapInfo9.5 and GeoDa0.95i to collect and analyze the data, this paper verifies the effectiveness and stabilization of the model. Empirical results show that the farther away from the metro stations, the smaller the magnitude of price appreciation for residence, showing the ladder-like diminishing law. Finally, this paper puts forward some policy suggestions for the urban rail transit to internalize financing of external benefits.