Abstract: The suburban ecological conservation areas in megacity are the focal point of conflicts between ecological protection and urban construction and the key zone of urban-rural integration. This paper took Mentougou District in Beijing as an example to introduce the planning practice of urban system planning and urbanization paths in this type of area under the context of territorial spatial planning, with a view to providing reference for relevant studies. Firstly, this paper carried out a comprehensive evaluation of townships, which was used as an important basis for subsequent planning, improving the scientificity of planning. Secondly, this paper built a modern and multi-level urban system, differentiated every planning unit according to their natural backgrounds, development bases and functional positioning. Lastly, this paper improved the implementation mechanism of the planning and clarified the path of urbanization and integrated urban-rural development of Mentougou, providing guidelines for town-level and village-level territorial spatial planning. This paper argued that county-level urban system planning under the context of territorial spatial planning should firmly establish the idea of ecological civilization and took zoning and classification as the guiding principle. Under the guidance of urban-rural integration purpose, the planning should promote the people-oriented new-type urbanization and implement the rural revitalization strategy.