[Objective] As one of the important ecosystem services, water conservation service is closely related to human well-being and is an important factor in guaranteeing regional ecological security and sustainable development of water resources, but currently there is a gap in the relevant research on the transition zone between north and south in China. This study aims to provide scientific references for water resources management by assessing the spatial and temporal evolution characteristics and influencing factors of water conservation in the southern Henan region. [Methods] In this study, we quantitatively assessed the water yield services and water conservation services in South Henan region from 2000 to 2020 based on the InVEST model, analyzed the spatial aggregation of water conservation with spatial autocorrelation, explored the main influencing factors of water conservation with the help of optimal parameter geodetic probes, and revealed the degree and direction of the influences of different factors on water conservation in localized space by combining with the geographically weighted regression model. [Results] The results show that: (1) From 2000 to 2020, the water production and water conservation in the southern Henan region show a significant downward trend, with the water yield decreasing from 3.56×1010m3 to 2.65×1010m3, and the water conservation decreasing from 1.87×109m3 to 1.23×109m3. (2) There is obvious aggregation in the spatial distribution of water conservation services in the southern Henan region, with “high-high” aggregation and “low-low” aggregation dominating. (3) Climatic factors are the main factors influencing the formation of spatial heterogeneity of water conservation, and socio-economic factors have less influence on it. (4) In the local space, precipitation, NDVI and GDP showed a positive effect on water conservation in South Henan, while the actual evapotranspiration and population density showed a negative effect. [Conclusion] Attention should be paid to optimizing the land use structure of the south Henan region, focusing on the middle part of the South-to-North Water Diversion Project, and reasonably allocating water resources to ensure its water ecological security and water environmental health, and to promote the sustainable development of regional water resources.