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This paper comprehensively summarized the research results from domestic and foreign studies of the effect of biogas slurry farmland application on plants yield and quality, and the effect on water and soil environment. It showed that biogas slurry played a positive role in improving the quality and yield of crops, improving plant seed germination, prevention and treatment of plant diseases and insect pests, and improving soil quality. However, an excess amount of biogas slurry application could lead to the pollution risks of water and soil environment. It should fully consider the land carrying capacity for biogas slurry and choose appropriate dosage which had no pollution on soil and groundwater, so that the demand of fertilizer could be saved and the production cost of farmers could be reduced. It could provide scientific guidance for biogas project handling biogas slurry. 