Abstract: In the context of global warming, shifts in precipitation, temperature, and potential evaporation exert a substantial impact on hydrological patterns and hydropower production. China endowed with abundant hydropower potential, places significant emphasis on hydropower in its energy portfolio. Investigating the effects of climate change on reservoir inflow and hydropower output is crucial for the sustainable development and utilization of water and hydropower resources. This study focuses on the Guanxi hydropower station, utilizing projections from 19 General Circulation Models (GCMs) in the CMIP6. The findings suggest: (1) Under the SSP2-4.5 scenario, temperature, precipitation, and potential evaporation are projected to increase in the coming decades. (2) Divergent GCMs yield varying projections; however, the overall trend indicates potential increases in inflow runoff and hydropower generation based on the mean of 19 GCMs. (3) Relative to the baseline (1981-2020), Guanxia hydropower station's inflow runoff is anticipated to rise by 3.55%−34.14%, 39.84% and 5.66%−32.27%, 41.96% in the near (2031-2060) and far (2061-2090) future periods, respectively. Consequently, hydropower generation is expected to increase by 5.87%−29.3%, 50.1% and 8.03%−27.3%, 52.4% due to changes in inflow runoff. These projected increments offer scientific support for the expansion of small hydropower station construction.