[Objective] The spatiotemporal evolution of water conservation services and its influencing factors in Southern Henan Province was explored, in order to provide decision-making references for water resources management in the north-south transition zone of China. [Methods] The water yield and water conservation services in South Henan Province from 2000 to 2020 were quantitatively assessed based on the InVEST model. The spatial aggregation of water conservation services was analyzed with spatial autocorrelation. The main influencing factors of water conservation services were explored with the help of optimal parameters-based geographical detector. And the degree and direction of the influences of different factors on water conservation services in localized space were revealed by combining with the geographically weighted regression model. [Results] ① From 2000 to 2020, water production and conservation services in Southern Henan Province showed a significant downward trend, with the water yield falling from 3.56×10¹⁰ m³ to 2.65×10¹⁰ m³, and water conservation declining from 1.87×10⁹ m³ to 1.23×10⁹ m³. ② There is clear aggregation in the spatial distribution of water conservation services in Southern Henan Province, with “high-high” and “low-low” aggregations dominating. ③ Climatic factors are the main elements influencing the formation of spatial heterogeneity in water conservation services; socioeconomic factors have less influence. ④ Locally, precipitation, NDVI, and GDP had positive effects on water conservation services in Southern Henan Province, whereas actual evapotranspiration and population density displayed negative effects. [Conclusion] Attention should be paid to optimizing the land use structure of Southern Henan Province, focusing on the central route of the south-north water transfer project, reasonably allocating water resources to ensure ecological security and environmental health, and promoting the sustainable growth of regional water resources.