Abstract: Heavy rainstorm is one of the main disastrous weather in Sichuan province,which can trigger secondary disasters and cause serious personnel casualty and economic loss.Based on the daily precipitation data of 5006 meteorological stations in Sichuan Province,this study adopts IDW method and ordinary kriging method to calculate the precipitation distribution for eight regional rainstorm processes,and calculate the area and area ratio of different precipitation grades.Meanwhile,the accuracy of calculation results are also assessed.The results show that:1) For eight regional rainstorm processes,the mean relative error of IDW and ordinary kriging method lower than 7%,so both methods have a satisfied accuracy for precipitation distribution calculation;2) In 2018,regional rainstorm mainly distributes in the northwest,south and southeast of the basin,while in the western Sichuan plateau and Panxi district the precipitation is relatively small.3) For eight regional rainstorm processes cumulative precipitation more than 50 mm,the area range from 20247km 2 to 158144 km² and the area ratio range from 4.17%-32.54%.Through analysis,we find that the rainstorm area can better reflect the impact range of a rainstorm process,and can also be used as a discriminant index of regional rainstorm.