Study regionThe Poyang Lake (PL) basin, located in the middle and lower reaches of the Yangtze River, China. Study focusThis study investigated the future precipitation variations during 2020–2100 under four shared socioeconomic pathways (SSPs) by downscaling the CMIP6 outputs using a new scale-based downscaling method, which integrated the GWR-KED method and time transfer matrices by linking the precipitation in the historical and future periods. New hydrological insightsCompared with the original CMIP6 outputs, the downscaled precipitation predictions exhibited large improvements, with mean absolute errors (MAEs) improved by a range of 37.49~66.81% and 74.95~75.38% on the seasonal and annual scale, respectively. The downscaled projections showed that the basin would be wetter at the annual scale during the next 80 years. Precipitation in spring would be increase over the entire basin under all future scenarios except SSP1–2.6. Parts of the PL basin exhibit drier trends under the four scenarios in summer, with the largest drying area occurring in the SSP2–4.5 scenario. Except in the SSP2–4.5 scenario, precipitation in autumn has increasing trends in all scenarios across the PL basin. Precipitation in winter shows a drying trend in some areas except in the SSP1–2.6 scenario, with the largest area occurring in SSP5–8.5. The results provide improved precipitation information for policy-making in water resource management and adaptation planning to mitigate Yangtze River floods in the future.