Water, energy and food are essential basic materials for human survival and development, and the supply mainly comes from ecosystems. With global climate change and rapid human socio-economic development, the demand for essential resources has surged, and the relationship between the supply and demand of ecosystem services has become tense. Clarifying the matching relationship between supply and demand of ecosystem services and optimizing the allocation of primary resources are significant to ecosystems' sustainable and coordinated development. The research on the relationship between ecosystem supply and demand has been extensive. However, the research on ecosystem services based on the water-energy-food nexus still needs to be completed. Taking Northeast China as an example, this paper firstly analyzed the spatiotemporal pattern, correlation and spatial matching patterns of water yield (WY), carbon sequestration (CS) and food provision (FP) supply and demand services by InVEST model, supply and demand index (SDI), and Spearman correlation analysis based on the perspective of the water-energy-food nexus. Secondly, based on five different spatial scales of provincial, municipal, county, watershed and grid, we further explored the spatial scale effect of each service. We determined the optimal spatial scale of resource management. Finally, according to the concept of "zoning control-classification strategy-hierarchical governance", an integrated water-energy-food management scheme and policy suggestions were proposed. The results showed that (1) From 2000 to 2020, WY and FP rose, and CS declined in the supply of services in Northeast China. Regarding spatial distribution, WY and CS were roughly high in the east and low in the west, and FP was high in the southwest and northeast, low in the northwest and southeast. WY, CS and FP were all on the rise in demand services, and the spatial distribution was roughly " high in the middle and low in the four sides. (2) The SDI of WY and FP rose, while CS was the opposite. SDI had spatial heterogeneity at different scales, with county scale being the most significant. (3) FP was the central functional division, and key management and control was the primary classification. It was urgent to improve the supply capacity of ecosystem services comprehensively. The study has crucial scientific reference value and practical significance for rationally allocating regional primary resources and sustainable ecosystem management. At the same time, the study is of great significance for the matching of ecosystem supply and demand services and the coordinated development of water-energy-food nexus in Northeast China.