Research progress of water ecological health assessment at home and abroad

China's Action Plan for Water Pollution Prevention and Control proposed to implement water ecological protection and water resource management in rivers and lakes. During the 14th Five-year Plan period, research on water ecological health evaluation methods of river basins, rivers and lakes should be carried out to support the transformation from water quality management to water ecological target in China, and provide basis for China's water ecological environment management needs. By combing the development process of water ecological health evaluation system abroad, several typical evaluation systems and methods such as prediction model method and biological integrity index method were mainly introduced and the limitations of the evaluation system through application cases were analyzed. The standards and norms related to water ecological health issued in China were combed, and the advantages and disadvantages of water ecological health evaluation methods in local watersheds in China were analyzed. Finally, some suggestions on China's water ecological health evaluation system, management criteria and policy system were put forward in order to provide reference for the research, development and practical application of water ecological health evaluation in China.