Abstract: The water discharge of Changjiang River Basin changed from abundant to obviously dry during flood season of 2022.Since July，Changjiang River Basin has experienced severe heat temperature and low precipitation，with decreasing water discharge and low water level，the water level of some hydrological station reached the lowest in the history of same period since recorded.In order to clarify the reason of change process from abundant to dry during flood season of 2022 of the Changjiang River Basin，this paper divided the flood season into three stages to analyze the spatial and temporal distribution of precipitation in the basin，and the changes of high-water and low-water of Changjiang River.And the low-flow recurrence periods of Changjiang River was analyzed considering the impact of reservoir regulation，the definition，characteristics and causation of low water of Changjiang River were revealed.Finally，based on the characteristics and causation of low water of Changjiang River Basin during flood season in 2022，this paper discussed the new needs for drought resistance in Changjiang River Basin.The results showed that after the mid-June，the rainfall turned from abundant to dry，the water from the upper，middle and lower reaches has dried up at the same time since July，and the degree of drought also gradually increased.In August，the middle and lower reaches of Changjiang River encountered 100-year low water.Through frequency analysis，this low water in the Changjiang River Basin was classified as severe low water in basin scale.The research results can provide reference for the future drought prevention in the Changjiang River.