Abstract: Human activities through the building and operation of dams and reservoirs have significantly altered the natural hydrological regime, leading to impairment of river ecosystem function and biodiversity. The concept of ecological baseflow emerged to mitigate the impact of dams and reservoirs on the hydrological processes. Based on previous studies, the fundamental concept of ecological baseflow was reviewed. The principles of ecological baseflow, as well as previously and currently used estimation methods were summarized. Challenges and possible tendency in the estimation of ecological baseflow were also presented.