Abstract: In order to implement the real-time capability of spaceborne SAR quick-look system, according to the characteristics of spaceborne SAR quick-look imaging algorithm, the impact from range migration that affects the azimuth matching is analyzed. As to the most time-consuming part in a quick look algorithm, the improved azimuth match algorithm is discussed in detail and realized. The optimized result indicates that the operation-amount descends by a tenth, and that realtime processing of quick-look system is realized.