In order to suppress the artifacts in the reconstructed target image obtained by the conventional back projection methods, a 2D scaled Wiener postfilter based method is proposed in this paper. Firstly, for a steppedfrequency continuouswave (SFCW) radar system, the frequency domain BP (FDBP) imaging method is formulated as a 2D distortionless beamformer. Then, the 2D Wiener postfilter with a scaling factor is adopted to minimize the mean square error of the beamforming result. At last, the influence of the scaling factor on the imaging performance for both single target and multiple targets is analyzed. Coherence factor (CF) based methods, which have been used for artifact suppression, can be interpreted as the special cases of the proposed method with different scaling factors. By selecting a proper scaling factor, the limitations of CF based methods can be overcome. Simulation results demonstrate that, both in range direction and azimuth direction, the artifacts in the reconstructed target image can be effectively suppressed by the proposed method.