Using the daily precipitation data of 8 national stations in Southwest Guizhou from 1991 to 2023 and 170 regional meteorological observation stations from 2014 to 2023, the climate change characteristics of summer rainstorm days in Southwest Guizhou are analyzed by using statistical methods such as trend analysis, Mann Kendall test, sliding t test and Morlet wavelet analysis. The results show that: (1) The national station in Southwest Guizhou has an average of 2.9 days of rainstorm weather in summer, and the correlation coefficient between the precipitation of the national station in summer and the total precipitation above the rainstorm in the same period is 0.83, and the contribution decreases year by year; The number of rainstorm days has declined since 1993. There are long-term periodic oscillations with a central value of 14 years and short-term periodic oscillations with a central value of 4 years and 10 years; (2) The average number of rainstorm days in summer is distributed in a "V" shape, with the largest number (13 days) in June and the smallest number in July. The number of rainstorm stations is decreasing month by month. The summer rainstorm weather process is the largest in June and has a wider range of influence. The number of rainstorm days in July is small but the range of influence is wider than that in August; (3) Local rainstorm occurs more frequently than regional rainstorm in summer, and the longest continuous rainstorm in recent 10 years is 8 days. (4) The distribution characteristics of rainstorm in each month of summer in Southwest Guizhou from 2014 to 2023 are as follows: the high value area of average rainstorm days in June is located in the north of the prefecture, the high value area of average rainstorm days in July is mainly located in Xingyi, and the high value area of average rainstorm days in August is located in Ceheng, Anlong, and the south of Xingyi; The rainstorm in summer is mainly concentrated in the area between 1000 and 1500m above sea level.