Abstract: In this paper,we simulated a rainstorm process in Sichuan province using conventional observation data,the equivalent blackbody brightness temperature（TBB） data and NCEP/NCAR reanalysis data（FNL）.The results show that the circulation pattern of “two ridges and one trough” in the middle and high latitudes and the superposition of subtropical high and continental high ridge formed the situation of “high in the east and low in the west” provided favorable background field conditions for the rainstorm process.The occurrence and development of several mesoscale clouds in the Sichuan Basin are directly related to the occurrence of heavy rain.The mesoscale model（WRF）reconstructed the heavy rain process in Sichuan.The positive area of 700 hPa vertical helicity can be a good indicator of the location and movement of the precipitation area.The high-altitude and high-altitude configuration of vertical helicity play an essential role in revealing the evolution of the convective system.