The Qinba Mountain area is located at the intersection of the northern and southern climates and biota in China, which has very important geographic and ecological values, and contains great potential for development. Determining the response threshold of ecosystem services to changes in vegetation cover is an important prerequisite for effective allocation of environmental resources, scientific formulation of management policies and maximization of ecological benefits in the Qinba Mountain region. In this paper, on the basis of analyzing the spatial and temporal characteristics of four ecosystem services, namely, water production, carbon sequestration, soil conservation and habitat quality in Qinba Mountain, we comprehensively used cluster analysis, analysis of variance (ANOVA) and elasticity analysis to compare the similarities and differences of the ecosystem services among different vegetation types and topographic gradients, and then calculated the thresholds of the impacts of the changes in vegetation cover in the different zones. The results showed that: (1) from 2000 to 2020, the water production, carbon sequestration, soil conservation and habitat quality services increased in general and showed a spatial distribution of high in the southeast and low in the northwest. (2) The overall supply capacity of ecosystem services of different types of vegetation was forest land, grassland and farmland in descending order. Under different topographic changes, except for habitat quality, which showed a continuous increase, the other three services showed a non-linear trend of increasing and then decreasing. (3) Vegetation cover had a promoting effect on ecosystem services, but this effect would gradually weaken after exceeding a certain threshold. The influence thresholds of vegetation cover were 0.85, 0.80 and 0.78 in the forest, grassland and farmland areas, respectively; and the thresholds increased and then decreased with the increase of topographic factors. The results can change the simplistic ecological protection mode of purely relying on the expansion of forest area to enhance the supply of ecosystem services in the Qinba Mountain area, and provide a basis for the construction of an ecologically sustainable development system that is managed in a zoned area, with a comprehensive system and a dynamic balance.