Abstract: Water yield represents one of the most critical ecological functions of rivers, and its changes directly affect the health and stability of fluvial ecosystems. Against the backdrop of global climate change, coupled with the influence of human activities, fluvial ecosystems worldwide have experienced degradation, with water production capacity decreasing considerably. Hydrological models, owing to their spatiotemporal flexibility, are widely employed to quantify and predict hydrological elements of river basins. Notably, the soil & water assessment tool (SWAT), known for its high portability and superior spatial heterogeneity representation, is widely recognized in the fields of hydrology and environmental science and has been extensively applied to hydrological simulations of large-scale river basins. Focusing on the Luanhe River basin, this study developed a SWAT-based river basin hydrological model to simulate and predict future water yield trends in the study area. The results indicate that from 2030 to 2060, the water yield of the Luanhe River basin will exceed the long-term average level in only nine years, exhibiting significant fluctuations in both annual and monthly distributions. This result suggests that intensifying trends of climatic warming-drying and increased frequency of extreme weather events significantly affect the water production process of the river basin. Pronounced spatial heterogeneity was observed in the water yield distribution among the sub-basins. In rainy seasons, the local maxima of water yield in sub-basins exceeded 100 mm. In drought seasons, the water yield difference between high- and low-yield sub-basins exceeded 10 times. These results further highlight severe water distribution imbalance among various sub-basins of the Luanhe River basin. Such imbalance can be mitigated through cross-sub-basin water diversion within the basin. The SWAT-based river basin hydrological model developed in this study enables simulation of hydrological responses of the Luanhe River basin under diverse development scenarios. The results of this study provide a valuable reference for projecting trends in the ecological functions of river basins under various pathways.