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Researches on drainage water reuse and its application in the irrigation district have great significance. In addition to safeguarding future food supply, drainage water reuse also raises the application efficiency of irrigation water and fertilizer, and protects the water environment. Basic theory and key technology of drainage water reuse at home and abroad were summarized, including the related study results of basic theory, several engineering modes for drainage water reuse, and management measures to alleviate the negative effects resulting from irrigation with drainage water. Through a systematic-analysis of the existing research results, it was pointed out that drainage water reuse had great potential in China, and it had great significance for water-saving and pollution abatement. The amount of research works about nitrogen and phosphorus in the drainage water was greater than those of salt and other components at present, and reuse engineering mode and irrigation management measures were the key factors affecting recycling effect. In the end, a study was put forward on the changing laws of drainage water quality and quantity, selection of optimal reuse mode, the best comprehensive management measures, evaluation for environment effect and research on risk analysis. These will be major themes of researches on drainage water reuse in the irrigation district in the future.