Based on the daily precipitation data of 104 stations in the Sichuan basin, a new method for identifying Regional Rainstorm Processes (RRP) in the Sichuan basin is established, and its temporal and spatial variation characteristics are analyzed. The research results show that the new method can rule out the influence of the isolated storm site, and identify the RRP quickly and accurately. There are 216 RRPs in the Sichuan basin, which have good correspondence with historical disaster data in time, range, and intensity. The number of RRPs in the Sichuan basin from 1961 to 2013 showed a gradual decrease. The integrated strength gradually increased from 1991 to 2013, which may be related to the duration and increase of accumulated rainfall. The method of rotating orthogonal function (REOF) is used to study the frequency of RRPs in three regions (northwest, northeast, and south). It is found that the most common is the northwest, the second is the northeast, and the south is the least frequently. For the three types of RRPs, the temporal variations are obvious, especially in recent 20 years. There is a trend of gradual decrease in the northwest of the basin, and increase in the northeast, while the south has no obvious change.