When building a runoff model based on the basin in which land-use changes are more,underlying surface change is an extremely important factor．By using the land resources classification system of Chinese Academy to divide the basin into some different land use types,consider separately the effects of evaporation and infiltration in every kind of underlying surface area,applying the runoff model coupling of infiltration-excess and saturation-excess runoff to do runoff calculations,using unit hydrograph and linear reservoir model to do the convergence calculations,thus runoff model based on underlying surface change was constructed．A frequency analysis was done for flood sequences of Zijingguan basin,before the model was calibrated and validated with flood sequences of different return periods．As a result of the simulation,the model structure basically reflected all aspects of runoff yield and concentration in the basin,simulation results can satisfy the required precision．