Abstract: Impacts of cumulus parameterization schemes, grid nesting approach and model resolution on the simulation of precipitation in July 2006 over the southern slope of the Tibetan Plateau have been studied by using WRF model. The result shows that the simulated precipitation is very sensitive to cumulus parameterization scheme. Different schemes have different results, and the result simulated by using Grell-Devenyi mass flux scheme is better than results using other schemes. The comparison of results of five sensitivity experiments indicates that, the use of cumulus parameterization scheme, the increased resolution, and the nesting approach can improve the simulated intensity and spatial distribution of precipitation. The simulation is better when these three approaches are used jointly. These approaches can improve the wind field simulation, which is beneficial for the simulation of water vapor transport and its convergence, and vertical heating and convection, and the distribution of vertical velocity. The simulated atmospheric humidity decreases without using a cumulus parameterization scheme, while model resolution and the nesting approach have little impacts on the humidity simulation.