Based on the ecological characteristics of the Biliuhe Basin,the calculation method of river ecological water demand is introduced in this paper.This method is applied in the profit regulation of the Biliuhe Reservoir in order to determine the river ecological water demand based on the ecological objectives.The results show that the basic and improved ecological water supply in the lower reaches of the Biliuhe reservoir are 27.65 million cubic meters and 42.5 million cubic meters,respectively.In order to pr...