Based on the envelopes and the characteristic of Doppler frequency spectrum of returns in single synthetic aperture radar(SAR) systems a method is proposed

which adopts two order Keystone Transform to adjust the range distortion of echo data

then the slopes of echoes’ envelopes are estimated to make some adjustments of walk and the Doppler parameters of moving targets are obtained through analyzing the Doppler frequency spectrum of the moving targets.At last the images and positions of ground moving targets are gained

which make it possible that the moving targets can be indicated in right positions in SAR image.In addition the key motion parameters of moving targets can be estimated by the relationship between the Doppler parameters and motion parameters of ground moving targets.The results of the simulative and raw data show that this method can image ground moving targets and estimate motion parameters effectively.