The invention discloses a water body remote sensing identification method based on U-net. The method comprises the following steps: A, carrying out data collection and preprocessing; b, carrying out preliminary extraction of a water body; c, processing a water body extraction result; d, making training and verification samples; e, training a U-net neural network model; and f, extracting water body. Two water body preliminary extraction algorithms are set through spectral analysis of different ground objects in each wave band of an image, all water bodies and part of other ground objects can beextracted, and a public truth value area, namely a preliminary water body result, is reserved. Classification post-processing, format conversion, modification, training and verification sample makingare carried out on an extraction result, a model is obtained through training of a U-net neural network model, and a water body is predicted. The method is suitable for regions with complex surface structures, is simple to operate and high in universality, can better eliminate interference of shadows, buildings and farmlands in the field steeping period, has a good extraction effect on small lakes and small ponds, and realizes accurate extraction of water bodies.