A method,called directed gradient power fractal feature extraction,was presented for object representation.In the method,we proposed the definitions and algorithms of directed gradient power,directed gradient total power,total directed gradient power,directed gradient power fractal feature,and complex number fractal feature.The properties of directed gradient power fractal features were analyzed and concluded.Two-dimensional fractal features were extracted for SAR image object detection.Theoretical analysis and experimental results show that by using the method,the objects of different shapes and scales can be detected efficiently.The method has the advantages of simple programming,faster computation,etc.