Abstract: The transmitting signal of inverse synthetic aperture Ladar (ISAL) has the characteristics of short wavelength and large bandwidth. When imaging an uniform motion target, dispersion in range direction and migration through resolution cells (MTRC) exist in the ISAL image. Therefore, the conventional range-Doppler imaging algorithm is inapplicable. The precise ISAL echo model was established for an uniform motion target, and the motion-induced range dispersion effect was analyzed in detail. In this paper, an ISAL imaging algorithm was proposed for uniform motion targets. The fractional Fourier transform(FRFT) was adopted to eliminate the range dispersion. By using the keystone formatting technique, the MTRC was compensated after a pre-coherent processing to the range-compressed signal. Finally, the high-resolution ISAL image was realized. Simulation results confirm the validity of the proposed imaging algorithm.