Abstract: Sequential floods, sequential droughts, and inter-seasonal alternation between droughts and floods are more frequent than ever before, due to rising global temperatures as well as human activities. Either of these compound events has an impact on vegetation vigor, crop growth and yield, water quality and optimal allocation of water resources. Therefore, it is urgent to accurately identify wet-dry complex events and understand their evolutionary characteristics and driving mechanisms to help develop adaptation strategies. While single drought or flood events have been investigated in some river basins in China, less attention has been paid to continuous flooding, continuous drought, or alternating drought and flood events, and the dynamics and driving mechanisms of wet-dry complex events are still unclear. Therefore, this study takes nine major river basins in China as the research object, analyzes the evolution law, spatial driving force, and dynamic change characteristics of inter-seasonal wet-dry composite events, and reveals the influencing factors of the dynamic change of wet-dry composite events.First, four types of wet-dry composite events were defined according to the drought and flood classification criteria, including dry-to-wet events, wet-to-dry events, continuous drought events, and continuous wet events, the standardized precipitation index was used to identify the wet-dry composite events between adjacent seasons, and the joint probability of occurrence of the four types of wet-dry composite events between the four seasons of spring-summer, summer-autumn, autumn-winter, and winter-spring was calculated using the Copula function; second, the Secondly, the Mann-Kendall test was used to explore the trend of the probability of occurrence of wet-dry composite events using a 20-year time series as a sliding window; finally, the driving factors of wet-dry composite events were explored using random forests.The results show that: 1) the spring-summer, summer-autumn and fall-winter periods between 1982 and 2022 are all more prone to successive drought events, with probabilities of 4.04%, 4.20% and 4.04%, respectively, and the winter-spring period is more prone to successive wet events, with a probability of 4.69%; 2) the inland river basins and the Pearl River Basin are prone to successive winter-spring drought events; Songliao River Basin, Huaihe River Basin, Yellow River Basin, Haihe River Basin and Southeastern Rivers Basin are prone to continuous wet events in winter-spring; Yangtze River Basin is prone to continuous wet events in summer-autumn; and Southwestern Rivers Basin is prone to continuous drought events in summer-autumn; (3) Nationwide, there are significant upward trends of continuous wet events in fall-winter and continuous wet events in winter-spring, and the values of the test statistics are 2.91 and 2.44, respectively. 2.91 and 2.44. From the analysis of different basin areas, the most obvious upward trend in the inland river basin, the Yellow River Basin, the Southeast River Basin and the Haihe River Basin is the autumn-winter successive wet events, the most obvious upward trend in the Songliao River Basin is the winter-spring successive wet events, the most obvious upward trend in the Yangtze River Basin is the spring-summer successive wet events, the most obvious upward trend in the Southwest Rivers is the autumn-winter successive drought events; (4) The spatial driving factors of the wet-dry composite events are mainly concentrated in the three major categories of factors, namely, sea-air coupling, land-air coupling, and precipitation. The dominant factor in the dynamics of composite events in most of the river basins in China is the meteorological factor, and the influence of the subsurface factor on the wet-dry composite events in most of the river basins in China is relatively small, but the influence on the Songliao River Basin is relatively large, especially on the summer-autumn and fall-winter successive drought events in the Songliao River Basin. The research results provide a basis for the precise defense of wet-dry complex events in China.