Effective utilization of water resources is one of the important prerequisites for the survival of human society, and remote sensing water body extraction technology plays a key role in water body planning and monitoring. For the water body extraction of Sentinel-1 SAR data, firstly, we analyze the backscattering characteristics of the water body and the main features around it, combine texture features and terrain features to make a comparative analysis using the existing extraction methods, and put forward the application strategies of the different methods for the typical water body environment in Poyang Lake, in order to more effectively extract the water body as a goal. The study shows that multi-feature fusion extraction reduces the confusion of water body information; the RF algorithm's fine water body and boundary extraction is relatively fine in comparison; while for the vegetation in shallow water, the threshold method demonstrates a better ability to recognize it; and the hulls of the boats covering the water surface have an impact on the completeness of the extraction of the water body area. The study explores the method applicability of Sentinel-1 SAR data in water body extraction in Poyang Lake, with a view to providing technical support for water resource monitoring in Poyang Lake.