Based on the monthly precipitation data of CN05 grid observation data set in Sichuan from 1981 to 2020, the overall variation trend, spatial distribution characteristics and temporal variation rule of summer precipitation in Sichuan were studied by means of EOF, REOF, trend analysis, M-K mutation test and Morlet wavelet analysis. The results are as follows. In the past 40 years, the overall variation characteristics of summer precipitation in Sichuan showe a decreasing trend, and the overall characteristics are more in the south and less in the north. The abrupt change occurred around 1982, and there are long period changes at the scale of 20 years and short period changes at the scale of 4-6 years and 8-12 years.