In the context of global climate change, the ecosystems' water conservation (WC) function has been significantly affected, particularly in peatland watersheds. This study focused on the Zoige peatland, a vital ecological barrier in the source region of the Yellow River (SRYR), to evaluate the dynamic changes in WC under various climate change scenarios. By improving the SCS-CN method in the Soil and Water Assessment Tool (SWAT) and integrating downscaled high-resolution meteorological data, this study quantitatively analyzed the contribution of WC to runoff (CWCR) and its spatiotemporal variation. Results indicated that from 1970 to 2023, the average precipitation, WC, discharge, CWCR, and WCR (WC rate) in the study area were 769.6 mm, 481.6 mm, 0.0049 m(3)/s, 91.28%, and 0.62, respectively. WC exhibited a strong positive correlation with precipitation (R-2 = 0.9498). Under the high radiative forcing scenario (SSP585), the region was projected to experience a hotter and wetter climate, enhancing WC functionality overall. However, the frequent occurrence of extreme weather events and ecosystem degradation will significantly weaken the regulation capacity of the region's WC functions. This study provides technical support for ecological restoration and adaptive management of peatlands.