In order to reveal the law of precipitation during the flood season in the Jialingjiang River Basin, based on the daily precipitation data of 11 meteorological stations in the basin from 1960 to 2020, the temporal and spatial evolution laws of the total precipitation and precipitation of different grades in the flood season (May-September) were analyzed using methods such as linear tendency estimation, Mann-Kendall non-parametric test, sliding t-test, re-scaling analysis, and contribution rate analysis, and the contribution of the change of precipitation days and precipitation intensity to the precipitation was quantified. The results show that: 1) The precipitation of the basin during the flood season is mainly moderate rain and light rain, and the total precipitation and precipitation of different grades all show an increasing trend, among which the precipitation of torrential increases the most. 2) The total precipitation and the precipitation of moderate rain, heavy rain and torrential rain are more in the east and southwest and less in the north, the overall difference between the north and the south is greater than that between the east and the west. 3) Except for the total precipitation in 1985, there no sudden change in the precipitation of different grades; the total precipitation, moderate rain and torrential rain in the future still show an increasing trend, while the light rain and heavy rain a decreasing trend. 4) The increment of total precipitation and the increment of moderate rain, heavy rain and torrential rain are mainly affected by the change of precipitation days, while increment of light rain precipitation mainly comes from the increase of precipitation intensity. The research results provide a scientific basis for the study of regional climate change and the utilization and development of water.