As the most concentrated area of human activities, cities consume a lot of natural resources and discharge a large amount of waste into the natural environment, which has a huge impact on the environment. Most of the ecological and environmental problems, such as environmental pollution, global climate change, and loss of biodiversity, are related to the city. How to coordinate urban development with the urban ecological carrying capacity is related to the destiny of the city itself, and also to whether its surrounding areas can successfully achieve the goal of high-quality and sustainable development. Based on collecting and reading a large number of literatures, this research deeply analyzes the research status and development myths of ecological carrying capacity, trying to refine the concept of urban ecological carrying capacity, and developing an evaluation method of urban ecological carrying capacity based on the supply and demand of ecosystem services. This study also discusses the ecological carrying capacity improvement logic and method, the integration and coordination of ecological carrying capacity, resource carrying capacity and environmental carrying capacity, and uses Beijing, Tongzhou sub-center and surrounding areas to conduct empirical analysis.

 The main contents and results of this research are as follows:

(1) From the aspects of system composition, carrying objects, characteristics of carrying supply and demand, environmental impact and supporting theoretical basis, etc., the theoretical system of urban ecological carrying capacity is reorganized. The urban ecological carrying capacity should emphasize the supply and maintenance of ecosystem services in the urban natural system and mixed system, distinguishing resources, environment, and ecological carrying capacity. Whether the supply of urban ecosystem services matches the needs of human survival and development is the key to evaluating urban ecological carrying capacity, and it is clear that ecosystem services are the object of urban ecological carrying capacity evaluation. (2) Based on the perspective of matching the supply and demand of ecosystem services, the urban ecological carrying capacity evaluation framework is constructed. Combined with multi-source spatial data and spatial model methods, the supply and demand of ecosystem services are spatially quantified. The Urban InVEST model is used to quantitatively analyze the service supply potential of the urban ecosystem. The HEV framework is used to describe the spatial heterogeneity of service demand, with the help of night-time lights data, population distribution data, urban road data, housing price distribution data, etc. The spatial differentiation of the supply-demand relationship of ecosystem services is formed. The priority areas for ecological carrying capacity improvement based on the pixel scale and the administrative boundary scale are obtained respectively. The results show that the sub-center and its surrounding area has a large and contiguous area in the first priority of ecological carrying capacity improvement, accounting for 56.93% of the entire area. According to the secondary zone and the specific type, the ecological carrying capacity improvement strategy of different zones is proposed. (3) Evaluation of the integration of urban ecology, resources, and environmental carrying capacity is proposed. The traditional indicator system standardizes indicators with different units and quantitative ranges, such as resources, environment, and social economy, and adopts a series of methods to obtain weights, and then add and obtain a comprehensive index, which lacks physical significance. This study uses the emergy method with the principle of ecological thermodynamics and uses a relatively stable and unified unit emergy value to convert incomparable items of different types of energy, resources, and services into a unified dimension to indicate the comprehensive carrying capacity of the ecosystem. The results show that the sub-center and surrounding areas contribute 22%, 59% and 19% to the overall resource carrying capacity, environmental carrying capacity, and ecological carrying capacity of Beijing, respectively, and the overall carrying capacity contributes 13.87%. (4) Based on the existing evaluation methods of ecological carrying capacity, the nexus framework of the correlation among ecological carrying capacity, resource carrying capacity and environmental carrying capacity is proposed, and the correlation methods are developed to quantify the coupling and synergy of ecological carrying capacity. It is found that the improvement of ecological carrying capacity has a driving effect on the improvement of resources and environment carrying capacity and vice versa. The coordination between the horizontal (sectoral) and vertical (cross-scale) aspects should be fully considered when the government policy is adopted to improve ecological carrying capacity.