Nature reserves are the cornerstones to conserve biodiversity and the effective way to sustain ecosystem integrity. It is significant to evaluate key ecosystem services in nature reserve and integrate them into the reserve management to improve the efficiency of ecological conservation and rehabilitation. Based on the CASA model, RUSLE model, InVEST model and the principle of water balance, this research evaluated the spatial and temporal distribution of four key ecosystem services in the Wolong Nature Reserve, including carbon storage (Net Primary Productivity), soil conservation, habitat quality and water conservation, covering period from 2000 to 2015. What's more, the variability of the four key ecosystem services at different terrain niche gradients and land use types were also analyzed and the hotspots of the four key ecosystem services were identified. Research results indicated that significant spatio-temporal heterogeneity existed for both four key ecosystem services provision and their changes during research period. Some conclusions could be derived as following:i)the average provision of four key ecosystem services increased during research period, and more areas with increase of key ecosystem services were found than those areas with decrease of key ecosystem services; ii)Distinct characteristic of spatial distribution heterogeneity were found. Areas with higher provision of the NPP(Net Primary Productivity), soil conservation and habitat quality were distributed in the southeast, while areas with lower provision of them were distributed in the northwest. The characteristic of spatial distribution did not change much and sustained relatively stable during research period; iii)Spatial distribution and changes of four key ecosystem services were related to terrain niche gradient and land use types. The areas with high provision and increase of the four key ecosystem services were dominantly located in lower terrain niche gradient, especially in the southeast area. With respect to the land use types, forestland and grassland had the outstanding contributions to the four key ecosystem services provision, and the most contribution came from forestland; iv)Hotspot analysis indicated that the hotspots of the four key ecosystem services were mainly distributed in the southeast of the study area, and the area of the hotspot of class Ⅳ, where four key ecosystem services provision were all higher than the average provision of whole study area, had increased significantly during the study period. According to the transfer matrix of hotspots, the variation characteristics of the hotspots showed a tendency towards ecological improvement. Finally, underlying driving forces were discussed, the spatio-temporal distribution and changes of four key ecosystem services could be closely related to local physical and socio-economic context. We hope the research results could be integrated into local ecological management policy and is helpful to improve local ecosystem restoration and biodiversity conservation.