Doppler beam sharpening(DBS)technique can provide reference for the location of the moving target detected to attack more accurately and effectively. DBS also can be used in trajectory navigation, landform matching, etc. In this paper, the basic theory of DBS imaging is introduced at first, then SAR processing method is analyzed which includes range cell migration correction technique and azimuth dechirping technique,and can improve image quality effectively in DBS imaging on SAR/GMTI mode. At last, some satisfying images by DBS based on the raw radar data are obtained.