To solve the problem of range dispersion and azimuth Doppler time-variation in echo when imaging maneuvering target with inverse synthetic aperture ladar, the accurate echo model of maneuvering target is built, and an imaging algorithm based on integral cubic phase function-fractional Fourier transform is proposed. In range compression, the integral cubic phase function is used to estimate the modulation frequency of the echo pulse quickly, and then the fractional Fourier transform is used to realize the range compression at the optimal rotation angle. In this way, the range dispersion is eliminated. After motion compensation, the integral cubic phase function-fractional Fourier transform is combined with the Clean technique to achieve the separation imaging of the strong and weak scattering points on each range cell, solving the problem of image defocusing due to the azimuth Doppler time-varying. Finally, the validity of the proposed method is verified by the simulation experiment of scatter point model.