Abstract:With the Weather Research Forecast(WRF) model, numerical simulation is carried out on a heavy rain in Sichuan basin during June 16-17,2011. Three representative stations located at different terrains were first selected, based on area and intensity of 24 h accumulated precipitation, then the simulation result of diurnal variation in precipitation was analyzed. The results show that the simulated hourly precipitation peak in Wangcang (the northeastern verge of the basin) is very close to the observation, but in Rongchang(the middle of the basin) and Yuexi(in the western Sichuan plateau), the hourly precipitation and 24 h accumulated precipitation are both quite different from the observations. Comparative analysis on the simulation result of three representative stations at different time points shows that heavy rainfall simulation is closely related to water vapor, dynamic and heating conditions in the simulation. The deviation of hourly precipitation was caused by the different simulation effects of the model on the water vapor, geopotential height,stream,vertical speed and atmosphere stratification at every time point, as well as the deviation of terrain altitude around the basin in the model.