A method for fault polygon extraction and smoothing is proposed in this paper. The method extracts fault polygon by boundary tracking algorithm, it uses the angle of fault polygon line and side length to smooth polygonal fault under the premise of keeping fault polygons form, and then enhances the fault polygon visual effects and aesthetics, it also provides a very good method for seismic data interpretation. After the validation in daqing oilfield seismic image, this fault polygon extraction and smoothing method can effectively extract fault polygons and remove the burr of fault polygon, the effect in fault polygon smooth is remarkable.