When synthetic aperture radar (SAR) imagines a moving target with high accuracy, the radial velocity of the target causes the range migration and the azimuth velocity causes the azimuth defocus，which will lead to the decrease of the signal-to-noise ratio and detection probability of the target. In this paper, a method of the series connection of range migration correction filter bank and azimuth matched filter bank is proposed to optimize the two-dimensional matching imaging of the multi-channel clutter suppressed data, which can reduce the residual clutter power and improve the focusing effect of moving targets. Then the CFAR detection is performed using adaptive threshold after each filter is imaged, and the output of multiple test results can be judged and fused. The results of simulation and measured data processing demonstrate the effectiveness of the method.