Concepts of boundary flow and contour flow, and a method of edge feature extraction, are used for object detection and recognition in SAR (Synthetic Aperture Radar) image. The method first used medial filtering, automatic thresholding, mathematical morphology binary filtering, and cross templet edge detection to extract pixel-based boundaries. Then, contour following was carried out and boundary flow entropy and contour flow entropy were computed to obtain the boundary flow features and contour flow features of target edges. Using the method, experiments of edge feature extraction of test images and SAR images had been done. The experimental results show that this method can describe the feature of objects well and also has the advantages of simple programming, faster computation, etc.