Ecosystem services (ES) are closely linked to human well-being, land use and land cover changes have significant impact on ecosystem functions. However, there are fewer studies on the evolution of ecosystems and their driving mechanisms in reservoir basins. the Miyun Reservoir basin, a water source in Beijing, was used as an example to analyzed the characteristics of land use changes from 1980 to 2020, and used the Patch-generated land use simulation (PLUS) model to predict the land use changes in 2050 under three scenarios. Then, the InVEST model and geographically weighted regression (GWR) were employed to investigate the spatio-temporal characteristics of ecosystem services and to quantify the effects of synergies and trade-offs between ES pairs. Furthermore, the mechanisms of drivers for the changes in the relationships of ES pairs were identified using the GeoDetector. The results showed that land use significantly changed in the MRB during the period 1980-2020, dominated by forest land and construction land; land expansion is the most drastic under the natural development (ND) scenario, while the most conservative under the ecological protection (EP) scenario. The spatial distribution of ES showed significant spatial heterogeneity, with the most notable changes in water yield and habitat quality concentrated in the western and northeastern regions of the MRB; the water yield decreased under the cultivated land protection (CP) scenario and EP scenario, while the habitat quality improved under the EP scenario. Significant differences existed in the relationships of synergies and trade-offs between ES pairs in the MRB, mainly influenced by natural factors, such as elevation, evapotranspiration and temperature. The results of this study provide valuable references for ecological management and optimization measures in the basin.