The study of the urban ecological carrying capacity is an important part of the urban research field，which is of great significance for guiding urban social and economic activities and coordinating the relationship between the city and the environment，and has more realistic significance for the cities which were restricted by natural regional environment. This paper takes Chaoyang City which located in Liaoning Province as an example，through combining system analysis theory and mathematical methods and applying urban sustainability calculation formulas which used qualitative to quantitative comprehensively integrated methods to construct a calculation model of urban ecosystem composite carrying capacity. The calculation results show that the current state of the ecosystem complex carrying capacity of Chaoyang City is higher than the ecosystem stress value. The city is in an ecological surplus period，and the consumption of urban natural resources is less than the amount of acquisitions which is in a state of sustainable development.