Abstract: Based on the hourly precipitation data of 39 meteorological stations in Dujiangyan City in the flood season of 2020, this paper analyzes statistically the temporal and spatial distribution of precipitation. The results show that: The cumulative precipitation in flood season was 1018.6~2206.6 mm, and the maximum precipitation in August was 948.1 mm. The extreme value distribution characteristics of 1 h, 3 h, 6 h and 1 2h precipitation was consistent, and the maximum values of 1 h, 3 h, 6 h and 12 h precipitation were 78.3 mm, 163.5 mm, 197.5 mm and 251.1 mm respectively. 1 h rainstorm mainly occurred from 23:00 to 07:00 the next day, the most occurred at 02:00. The heavy rain was mainly concentrated from 00:00 to 06:00 the next day, the most occurred at 02:00. There were 24 extraordinary rainstorms, all of which occur from 23:00 to 06:00 the next day, and there was no extraordinary rainstorm during the day (08:00 to 20:00); The average days of extraordinary rainstorm and above in 1 h, 3 h, 6 h, 12 h and 24 h were 9.7 d, 12.9 d, 13.8 d, 15.3 d and 8.7 d respectively.