Guizhou Province, a typical karst region, experiences abundant rainfall but exhibits weak water conservation (WC) capacity. In this study, the InVEST water yield model was employed to quantify long-term WC dynamics (1983-2022). Spatiotemporal trends were analyzed using Mann-Kendall tests and Sen's slope estimator. Additionally, the response of WC to climate and land use drivers was further discussed. The results showed that the average annual WY and WC were 547.62 mm and 364.70 mm (in depth), respectively. The spatial distribution exhibited high in the east and low in the northwest. WC showed a decreased trend in the west and increased in the east from 1983 to 2022. The spatial analysis emphasized that high-WC areas should prioritize natural protection, while low-WC regions require artificial restoration, particularly significant decreasing trends that need urgent intervention. Variations in WC were driven by the combined effects of climate factors and land use types, with forest land and grassland demonstrating the highest WC capacity. This study clarifies the spatiotemporal evolution and driving mechanisms of WC, providing scientific support for maintaining and enhancing WC strategies in Guizhou Province.