In order to improve the control of land use in China, taking Sunan Yugur Autonomous County in the Qilian Mountains area as an example, this paper explores the method of national ecological space delimitation and zoning based on ARCGIS platform. Three kinds of space division techniques are formed to unify natural resources survey data, carry out land spatial suitability evaluation, delimit three kinds of space and optimize natural ecological space division. According to existing laws in China, based on ecological protection red line, natural ecological space is divided into ecological protection red line and general ecological space. According to the regulation requirements and the functional division of various protected areas, the red line area of ecological protection is divided into core protected area, ecological restoration area, traditional utilization and recreation area with the area of 3 947.28, 3 216.89 and 6 936.56 km2, respectively. In view of the prominent problems in the process of delimitation and zoning of natural ecological space, some suggestions are put forward, such as unification of chassis, optimization of ecological protection red line and coordination and unification of management boundary.