The Yellow River Basin is an important ecological barrier in China. With the increasing interference of human activities, the ecological problems of the Yellow River Basin have received more attention from the academic community. On April 1, 2023, the Yellow River Protection Law of the People's Republic of China was formally implemented, which explicitly required to strengthen the synergistic management of the Yellow River's water resources, water environment, and water ecology in order to realize the harmony between human and nature. It is of great significance to study water conservation service function to promote ecological protection and high-quality development in the Yellow River Basin. Based on the InVEST model, this study quantitatively evaluated the water conservation service function of the Yellow River Basin from 1980 to 2020. We analyzed the spatial distribution pattern of the water conservation service function by the spatial autocorrelation and analyzed the factors affecting change of the water conservation service function via geographical detector. The results showed that: (1) the water conservation volume of the Yellow River Basin from 1980 to 2020 ranged from 17486.39 million m³ to 37845.38 million m³, with the averagely annual water conservation volume of 26504.75 million m³. The multi-year average water conservation volume of the grassland and forestland accounted for 52.94% and 24.27% of the total water conservation volume in the Yellow River Basin, respectively. A higher distribution pattern in the upstream and downstream regions and a lower distribution pattern in the middle reaches were presented. (2) The global Moran index was 0.875, indicating that the spatial distribution of water conservation service in the Yellow River Basin showed aggregation distribution, which was dominated by low-low aggregation and high-high aggregation. (3) From 1980 to 2020, the order of average water conservation amount of different land types was shrubbery>forest land>high cover grassland>other forest land>medium cover grassland>low cover grassland>dry land>construction land>unused land>paddy field>water area. (4) Precipitation was the main driving factor affecting water conservation in the Yellow River Basin. The interaction between precipitation and land use significantly enhanced the explanatory power of spatial differentiation of water conservation service functions in the Yellow River Basin. The results could provide an important reference for the ecosystem management and high-quality development of the Yellow River Basin. Regarding the uncertainties of the methodology and model, research on parameter localization should be strengthened. More social and economic factors should be taken into account such as population and GDP in the future.