Abstract: Central urban area is an important concept and planning level of county(city) level overall planning, but there have been problems for a long time such as unclear concept connotation and non-standard demarcation method. This paper adopts the method of combining theoretical research with project practice. Firstly, the concept of central urban area and related research are analyzed and sorted out, the concept and connotation of the central urban area district is proposed based on the requirements of the territorial spatial planning system. Secondly, the technical process of determining the central urban area is put forward based on the technical rules of determining the urban area and the requirements of demarcating the urban development boundary. Finally, the central urban area of Yongji County, Jilin City, Jilin Province is selected to verify and optimize the method, to guarantee the method is standardized, reasonable, and easy to operate. It is expected to provide reference for the subsequent planning approval, physical examination evaluation, and regulation standard revision.