Abstract: Scattering centers of actual radar target are different from the ideal scattering centers. They have strong dependences of scattering amplitudes and positions on aspect angles of radar line of sight. Based on the aspect dependences, this paper presents a simple and effective method to reduce the complexity of imaging data. The effective observation angle of each scattering center is analyzed and estimated, and only the scattered fields under the effective observation range are selected for imaging. The image characteristic obtained by less observation angle is the same as the image characteristic obtained by wide-angle imaging. The numerical results show that the ratio of data reduction for the cone-shaped target is over 45%, and 80% for the airplane. The research results of this paper are of significance to the radar imaging and image characteristic recognition.