Abstract: When imaging maneuvering target with Inverse Synthetic Aperture Ladar (ISAL), dispersion and Doppler frequency time-variation exist in the echo signal in range and cross-range direction, respectively. For targets of which the maneuverability can be approximated as a second-order motion, the characteristics of the ISAL echo signal are analyzed, and an imaging algorithm based on FRactional Fourier Tronsform(FRFT-CLEAN) is proposed. FRFT is used for range dispersion elimination. After motion compensation, a method combining FRFT and CLEAN technique (FRFT-CLEAN) is proposed for azimuth imaging. Simulation results demonstrate the validity of this algorithm.