Abstract: Usually,the range migration through resolution cells which results in an image badly unfocused makes fast moving target hardly detect.Additionally,PRF ambiguity which results in Doppler spectrum folded strongly impairs accurate position. A method for ground fast-moving target detection,position and imaging based on the tri-channel airborne SAR-GMTI is presented in case of the problems above.Firstly,DPCA is used for clutter suppression when implemented on range compressed and azimuth-uncompressed data.The Canny operator,ratio operator and Hough transform are combined to extract the moving tracks.Then a method based on two-order Keystone transform after resolving PRF ambiguity is used for target imaging,detection and motion parameter estimation.Finally,the slow and fast-moving targets are together labeled on the SAR image.The results on raw data show the efficiency of the proposed method.