Soil conservation is an important service function of an ecosystem. Therefore, the study on soil erosion and mass and value of soil conservation of a valley may provide some essential bases for soil-water conservation, regulation of land use patterns,eco-compensation and reservoir management in the areas of the Project of Water Diversion from South to North. For that end, Shangluo, a major water source region of the project, was cited for quantitative evaluation and spatial heterogeneity analysis of the ecological service functions of land retension, soil erosion and soil conservation therein from the angle of hydrology, using the sediment retension sub-model of the InVEST ( Integrated Valuation and Trade offs of Ecosystem Services) model to ensure accuracies of in-situ acquisition, verification, colliberation and input of parameters, and for further exploration of benefits and spatial characteristics of the soil-water conservation pracices of ensuring water quality and desiting in the region, in expectation of providing some theoretical basis and reference to decision-makers.. Results show that (1) the total potential and actual soil erosion rate of Shangluo City was 1.21×10⁹ t and 3.4×10⁷ t, respectively, implying that the region, on the whole, was rated “slight” and “moderate” in soil erosion and had no sign of severe erosion, and the five watersheds (Luo River, Dan River, Jinqian River, Qianyou River and Xun River) in the region were all in the categories of slight and moderate erosion; (2) The total sediment output from the region was 1.61×10⁶ t，whereas the total soil retention rate of the region was approximately 1.17×10⁹ t, of which 2.9×10⁷ t was of sediment, and among the five watersheds, Xun River, Jinqian River and Qianyou River were very high in sediment retention capacity; (3) the total ecological service value of the soil conservation in the region reached 205.5 million yuan and 616.3 million yuan in terms of reduction of sediment accumulation and insurance of water quality and was averaged to be 313.6 yuan hm^-2 a^-1and 824.1 yuan hm^-2 a^-1, excluding the consideration of dead reservoirs; and (4) to prevent and control soil erosion, priorities should be given to optimization of land use, improvement of regional ecological benefit, development of forestry and amelioration of the soil and build-up of soil and water conservation capacity, which should start from small watersheds, with special attention to soil-water management of forest-grass interlaced areas, terrace fields on slopes and ridge-furrow tillage and construction projects.