Abstract: Since the proposal of requirement for delimiting of urban developing boundaries by the Central Urbanization Conference and "National New Urbanization Plan (2021-2035)", it has come to be more and more mature in terms of delimiting of urban developing boundaries in urban areas, but it provided limited assistance and benefit for the work of in different levels of district and county units. This article starts form the most optimal angle to analyze the district and county units' choice and route about ecology control, developing manner, planning implementation under the background of spatial connotation development, which proposes an optimal constructing project for overall thinking, technical realization, system guarantee of urban development boundary system demarcation, as well as provides references for the delimiting practice in district and county units.