In this study, 96 Environmental Impact Assessment (EIA) reports of hydropower projects from 2001 to 2015 have been collected, and four parts of the contents including the project status, hydrological characteristics, downstream fish status and ecological flow have been analyzed by statistical methods. Thus, we built the ecological flow database of hydropower projects in China, and analyzed the differences of ecological flow release before and after the implementation of the 2006 guideline, based on spatial and temporal characteristics analysis in ArcGIS platform. We also analyzed differences between the calculation methods, release types, safeguard measures and monitoring measures of ecological flow. Meanwhile, we analyzed the ecological benefits of insurance for endangered fish protection. We focused on the effectiveness of ecological flow guarantee and shortages after the 2006 guideline. Therefore, ecological flow practices on hydropower projects in China have been summarized, and we suggested 17% of annual average flow as the ecological flow constraint red line, combined with the flow process demand. Then we put forward the prospect of ecological flow research and practice in China, by strengthening the research of calculation principles, cascade reservoir operation and ecosystem recovery and rehabitation.