Water conservation is one of the most important service functions of the ecosystem, and the outline of the Yellow River Basin Ecological Protection and High-quality Development Plan emphasizes focusing on key areas and restoring important ecosystems, which puts forward new requirements for strengthening water conservation capacity. We collected and analyzed meteorological and subsurface data of the Yiluo River basin from 1975 to 2019, calculated the water yield of the basin for a total of nine time periods in every five-year period during 1975 to 2019 using the water yield module of the InVEST model, and the water conservation was obtained by using the flow rate coefficient and soil saturation conductivity to correct the water yield. This study specifically analyzed the characteristics and correlations between precipitation, water yield and water conservation in the Yiluo River Basin.The results show that from 1975 to 2019, the annual average water conservation in the Yiluo River Basin is 11.3 mm, and the annual average water yield is 143.2 mm, and the overall water yield and water conservation show a trend of first increasing and then decreasing, reaching a peak from 1980 to 1984. The spatial distribution of water conservation capacity in the river basin is characterized by abundant vegetation in the upstream and strong water conservation capacity in mountainous areas of earth and rock, while the middle and lower reaches are relatively weak. The results of single-correlation and complex correlation analysis of meteorological elements in the basin show that the water conservation capacity is significantly positively correlated with precipitation, but not with evapotranspiration of reference crops. To a certain extent, the change of land use in the river basin affects the spatial distribution of water conservation capacity, and the areas with high value of water conservation in the upper reaches and the areas where farmland is returned to forest and grassland are significantly affected. The results can provide a reference for the assessment of water conservation capacity in similar river basins.