To quantitatively analyze the impact of different land uses on the stormwater flooding process, a catchment hydrodynamic model was adopted to simulate the surface runoff process of Wangmaogou River Basin under different land use scenarios, meanwhile the reductions of peak discharge were compared and analyzed. The results show that the location of the forest land has a great influence on the runoff compared to the other land uses under the rainfall return period of 2 a, 10 a, 50 a and 100 a. When the forest land is located in the downstream of the basin, it has the largest reduction effect on the peak discharge. As the rainfall return period increases, the peak reduction effect of the forest land in the downstream of the basin becomes more remarkable. This study can provide practical guidance for the optimization of land use layout in the basin.