In China, the county development is very important in promoting the national economy, coordinating the relationship between the city and rural area and achieving sustainable development of the country. The norm of county planning is a document directing the development of the total county area. Therefore, based on the theory of man-land system, this paper discusses the key in drawing up a county planning, such as regulating the economic structure, arranging the town system and protecting the eco-system. Finally, a draft norm of county planning was put forward.