Residence time serves as a critical indicator of lake water renewal and exchange, directly influencing pollutant transport and migration processes, and consequently water environment of the lake. In recent years, the hydrological conditions of Poyang Lake have undergone substantial changes, which have significantly influenced its water environment. This study focuses on residence time as a crucial hydrodynamic parameter for assessing water quality. Using the MIKE21 hydrodynamic model coupled with a tracer model, the research quantitatively examines the spatiotemporal distribution characteristics of residence time during the receding period of Poyang Lake from 1980 to 2020. Additionally, the study investigates regional interannual variation trends and clarifies the response relationship between residence time and hydrological conditions. The results reveal that the residence time during the receding period of Poyang Lake is characterized by high spatiotemporal heterogeneity. The average residence time for the entire lake is 36 d, with variations among sub-regions: eastern lake bays (93 d) > southern lake area (53 d) > northern channels (38 d) > main lake area (26 d) > seasonal isolated lakes of Wucheng (17 d). Over the past 40 years, certain areas of Poyang Lake have experienced a slight decreasing trend in average residence time. After the operation of Three Gorges Dam, the average residence time of the entire lake decreases by about 4 d, with the northern channels exhibiting the largest decrease (9 d), followed by the main lake area (5 d); other regions show minimal change. The residence time during the receding period of Poyang Lake is significantly longer in wet years compared to dry years. A strong positive correlation exists between residence rate and water level during the receding period. The shortened residence time during the receding period in Poyang Lake is primarily attributed to the decreased water level and the accelerated recession rate. The results of this study can provide scientific support for the water environment governance and ecological restoration of Poyang Lake.