In order to divide rainfall events and analyse rainstorm characteristics in Zhenjiang City, based on the minute rainfall data of Dantu Station from May to October in flood season from 1981 to 2016, the rainfall interval time was determined, the rainstorm frequency and rainstorm quantity variation characteristics of each month in flood season were analyzed, and the evolution law of rainstorm with different duration and intensity was analyzed. The results show that the reasonable rainfall interval of Zhenjiang City is 2 h. The total number of rainstorms in flood season showed a slight upward trend, and the total storm rainfall increased at the speed of 43.4 mm every 10 years. The rainstorm in flood season was mainly concentrated in June to August, and the rainstorm frequency accounts for 73.0% of the total rainstorm frequency in the flood season, and the rainstorm amount accounted for 73.5% of the total storm rainfall in the flood season. In July and August, the rainstorm and its contribution rate to the total rainfall showed an increasing trend, while in other months it showed a decreasing trend, and the rainstorm concentration increased. Among the rainstorms with different durations, the general rainstorm accounted for the largest proportion, and the number of extreme short and short rainstorms increased significantly, and the intensity of extreme short rainstorms showed an increasing trend. Among the rainstorms with different intensities, the weak rainstorm accounted for the largest proportion, and the number of moderate and heavy rainstorms increased in different degrees.