Generally, our detection technique detects man-made targets of interest when those targets are a small percentage of a nature background. If we use one threshold for the integral field, some nature background would be divided to wrong kind of areas. In this paper, the intrinsic difference in fractal features between natural background and man-made objects is presented. By the discussion of its characteristic using wavelet composition, the fractal dimension and the error of fractal feature after multiscale decomposing is used to detect man-made targets in natural background. Our experimental results for real images show that the procedure in this paper is applicable.