Unraveling the complex interactions between ecosystem services is a prerequisite for managing multiple ecosystem services simultaneously. As the core ecological barrier of the upper reaches of the Yangtze River, the study of the spatial differentiation characteristics of ecosystem service interactions in Sichuan Province is of great scientific value and practical significance for maintaining the ecological security pattern of the Yangtze River basin and coordinating the contradiction between ecological protection and food production in the southwestern region.

Based on ArcGIS 10.8, this study assessed four ecosystem services, namely carbon sequestration, food production, water conservation and soil conservation, and analyzed their spatial and temporal change characteristics as well as quantified the trade-offs and synergies among them in Sichuan Province.

1) Ecosystem services are spatially heterogeneous, with high values distributed in the east-west transition zone region and the southern region, and low values distributed in the western alpine plateau region and the eastern basin region. It is more stable in time change, showing a trend of decreasing and then increasing; 2) Trade-offs occur between food production and other ecosystem services, and synergies occur between carbon sequestration, water retention and soil conservation services. synergies between ecosystem services show an increasing trend over the period 2000-2020; 3) Forest land makes the greatest contribution to the three ecosystem services (carbon sequestration, water conservation, and soil conservation). The reduction in the area of arable land has a significant impact on the supply of food production services.

The spatial and temporal distribution of the four ecosystem services is characterized by heterogeneity and stability, and synergistic effects are dominant among the services. The spatial and temporal evolution of ecosystem services and their trade-offs and synergistic relationships in Sichuan Province are clarified to provide theoretical basis for regional sustainable development.