In order to maintain the optimum ecological health for the downstream of Heihe River, it is necessary to analyze the ecological water demand in the downstream of Heihe River respectively from two aspects that artificial and natural ecological water demand, then the ecological water demands in the downstream of Heihe River of current situation and 2015 are determined in this paper, which are 962 million and 1.048 billion cubic metres. At the same time, some integrated measures for repairing and improving ecology for the downstream of Heihe River, including ecological water transporting project, ecological restoration project and ecological immigrant project, etc., are put forward in this paper, so as to guarantee the ecological safe for the downstream of Heihe River. Overall, all of these have the important practical significance for protecting the local ecological environment, supporting the local sustainable economic and society development, and guiding comprehensive treatment of the Heihe River basin.