Summer rainfalls over North China in 1996 are simulated using regional climate model (RegCM3), and the simulation results are compared with the observed precipitations to investigate the model's capability to reproduce the daily variation of summer rainfall.Based on that, the terrain effects of Taihang Mountain on three heavy rainfall processes over North China have been investigated by orographic sensitive experiment.Results show that the model can reproduce the spatial distribution of the summer rainfall, which are consistent with the observations in aspects of location and shift of the rainfall belt during three typical heavy rainfall processes.But the model overestimates the quantity of the rainfalls.The orographic sensitive experiments indicate that the topography of Taihang Mountain plays significant but different roles in the three events of heavy rainfall.When the rainstorm mainly occurred over Taihang Mountain, easterly flow is resisted and lifted by the mountain, therefore increase the rainfall over the two slopes of Taihang Mountain;while the rainfall obviously decrease on both sides should the mountain removed.For the returning-flow rainstorm type, the topography significantly influences both the location and westward movement of the rainfall.While for the eastward moving rainstorm type, the topography only changes the intensity of rainfall but has little influence on the rainstorm location and related circulations.