Abstract: From the point of view of realizing the sustainable socio economic development in loess plateau,this paper discusses the def init ion of the eco-environmental water demand and the framework for computing eco-environmental water demand in loess plateau,aiming at sustainable development of eco-environment.Taking Jinghe river basin in loess plateau as an example,the average yearly ecological water ewquirement for soil conservation measures is estmated as 6.5368×10⁸m³ in 1970-1996.The research not only enriches the theory of the eco-environmental water demand,but also provides a scientific basis for the eco-environmental construction and the exploitation and utilization of water resources.