Abstract: Meiyu in the middle-lower Changjiang River and the autumn rain of west China usually happen before and after the main flood season of the Three Gorges Reservoir(TGR),which are important bases for judging the flood coincidence and impoundment time.This study analyzes the spatiotemporal distribution of autumn rain and Meiyu, flood season division in TGR based on 7d and 15d flood volume series and its corresponding influence on impoundment operation at the end of flood season.It is shown that Meiyu occurs in the early main flood season of the TGR,while the autumn rain begins on August 21.In the end of Meiyu on August 8,the flood control pressure in the middle-lower Changjiang River is relieved, and the TGR can release the flood prevention storage capacity allocated for Chenglingji area in advance.When the TGR enters the post-flood season on August 29 with moderate flood magnitude, it can start refill operation in advance to use autumn flood resources.Considering the key time nodes of Meiyu, autumn rain and TGR flood season division, it is suggested that the TGR can implement dynamic control of water level and early refill operation after August 8 on the premise of ensuring flood control safety.