Abstract: Water resources are the basic and strategic natural resources, and also the key element of land space management and control. There is a complex relationship between water resources and land space planning. This paper takes Gaoxigou as an example, a demonstration village of the ecological management in Mizhi County, in Loess Plateau of northern Shaanxi, and carries out the researches of the evaluation for water resources carrying capacity, the optimization of land space based on the rigid constraints of water resources. The results show that: ①in the current situation, Gaoxigou village mainly depends on groundwater resources, which is extremely scarce. The utilization rate of water resources is high. It is very difficult for the further development. So the exploitation potential is small, and it has reached an overload state. The groundwater quality rate is the level of poor or very poor. The main exceeding factors are: Cr⁶⁺, SO₄^2- and TDS, which needs to be treated before they can be used as domestic water.②Considering the irrigation mode, the rate of the water-saving irrigation, rainwater harvesting technology, irrigation ratio, the scale of the research activity, combined use of multiple water sources, etc., the four water resources utilization scenario sets are constructed for the prediction of water resources carrying capacity. The simulation result shows that it is overloaded. ③Land space planning of Gaoxigou village should be strictly controlled under the constraints of water resources and ecological red line, and advocate the water-saving technology of dry land farming, and improve the irrigation system, and control the scale of tertiary industry such as research tourism, and strengthen the joint regulation of water resources, then build perfect water supply and drainage facilities. The optimization results of rural land space planning based on the rigid constraints of water resources provide a scientific basis for Gaoxigou village and other similar areas.