Abstract: The scientific demarcation of urban development boundary is the main content for the national territory spatial planning, as the core control boundary of urban development, it plays a dual role of control and guidance in the process of urban development. At present, the research on the urban development boundary generally focuses on large and medium-sized plain cities, and lacks the discussion on mountain tourism cities with high degree of land dispersion and the connection with the regional allocation of construction land quotas. According to the practice of Jiuzhaigou County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, this article discusses how to analyze the more suitable newly-added construction land from regional tourism perspective on the basis of double evaluation, and define the allocation criterion by evaluating the development potential of towns, and finally forms the method of demarcating the urban development boundary by building the technical framework of the seven-step method, which plays a positive role in optimizing the landscape pattern and promoting the green development of cities.