Abstract: Ecological water requirement is an important research content of ecological hydrology. Progress on the research of ecological water requirement was analyzed. According to the concept and relative concept of ecological water requirement, generalized and narrow concepts of ecological water requirement were defined. Generalized concept of ecological water requirement is the total water amount that ecosystem require to keep the balance of water resource under the certain ecological targets; while narrow concept of ecological water requirement is the runoff that ecosystem consume to maintain the ecological and environmental function of ecosystem. Ecological water requirement of land and water ecosystem have been researched. Theory and calculated method of ecological water requirement of river system, vegetation system including farmland, wetland and lake system were stated and summarized. The further researches of ecological water requirement should be focused on the basic theory research, quantitative method and coupling method of ecological water requirement. Ecological water requirement for the different targets of ecosystem protection should be mainly discussed for the further study.