Abstract: Based on the 1 h and 3 h extreme rainfall data of Sichuan Province from 1961 to 2021, the frequency analysis and calculation of the extreme rainfall in Sichuan Province are carried out by using the regional linear matrix. The results show that the optimal linear distribution of the 1 h and 3 h extreme rainfall in Sichuan Province is similar. The optimal linear distribution of the western Sichuan Plateau and the Panxi region is mostly generalized extreme value distribution, and the optimal linear distribution of the Qingyi River rainstorm region in Sichuan Basin is generalized normal distribution; The basin surrounding mountainous areas at different time periods contain three types of linear patterns: GEV, GLO, and generalized normal distribution. The distribution of GLO is more advantageous in calculating extreme rainfall. The research results of this article have important reference in the defense of mountain flood forecasting and early warning in small and medium-sized watersheds in Sichuan Province.