Abstract: In order to satisfy the requirement of space planning, the authors have constructed the prohibitive and restrictive factors of suitability evaluation of construction land and cultivated land with natural geographical condition and institutional policy. In the evaluation, firstly, the restriction of specific indicators on dierent functions such as agriculture and construction in the region is qualitatively analyzed, and the prohibitive indicators such as ecologically important or extremely sensitive areas and waters are "vetoed by one vote". Then, different index grades and weights ae set for comprehensive scoring. The prohibitive factors mens "no" for construction land and cultivated land, and the restrictive factors are limited by value(0~100, the higher the better) and the weight on the suitability. Combined with the evaluation of ecological importance and sensitivity, based on GIS technology, and comparing the suitability grades of ecology, agriculture and construction in the same plot, the authors determine the space types according to the highest level of the three. If the suitability grades ae the same, the space types are determined according to the specific resource and environment attributes of the plot and the current situation of land use, and the ecological, agricultural and construction spaces are adjusted and optimized according to the integrity of the ecosystem and the needs of agricultural modernization. Taking Hu'nan Province as an example, the authors divided the whole space into the construction with development space (20.22%), the agricultural development space(30.3%), the ecological protection space(49.48%).