Abstract: National parks have extremely high natural elements and ecological values. As the only national park in the Yangtze River Delta, the study of ecosystem services in Qianjiangyuan National Park is beneficial to the management of ecological assets and sustainable development of the region. Therefore, this paper explored the evolution of ecosystem services and measured the trade-off synergistic relationship among ecosystem services in Qianjiangyuan National Park over the past 30 years.Based on the InVEST model, four eco-services, including water supply, soil conservation, carbon sequestration and oxygen release, and habitat quality, were evaluated from 1990 to 2020, and the temporal and spatial evolution law was explored. The ecosystem services trade-off synergy model (ESTD) was used to analyze the trade-off synergy between ecosystem services. (1) The total quality of ecosystem services in Qianjiangyuan National Park showed an increasing trend, among which water supply services decreased from 2.39×107m³ to 1.92×107m³, and the quality of soil conservation, carbon sequestration and oxygen release and habitat quality services continued to rise. (2) From the spatial pattern perspective, the spatial pattern of the water resource supply service obviously changed, while the other ecosystem services were relatively stable. The area of class Ⅳ hotspots of ecosystem services increased from 7.78 km² to 12.75 km². (3) The relationship between ecosystem services was mainly synergy, and the synergistic relationship was mainly among soil conservation, carbon sequestration and oxygen release, and habitat quality. The trade-off relationship existed between the water resource supply service and the other three services. (4) The changes in land use type, the changes in conditions related to specific ecosystem services, the implementation of relevant policies and special plans, and the interference of human activities are the main factors affecting the spatial pattern and trade-off/synergistic relationship of ecosystem services in Qianjiangyuan National Park. The spatial and temporal evolution pattern of ecosystem services and the trade-off synergistic relationship of Qianjiangyuan National Park changed significantly over the past 30 years, and the dominant influencing factor is the land cover change. The current spatial pattern of the ecosystem services in the park was higher in the west and lower in the east in 2020. Thus, in the future, efforts should be focused on optimizing the functional zoning of the park, gradually exploring and improving the national park management system, and balancing the relationship between ecological resource protection and human socio-economic development.