Accurately understanding the effects of phase fluctuation on the laser beam propagation through the atmospheric turbulence, and then making an effective wavefront correction will improve the imaging ability of practical synthetic aperture ladar systems. Based on the phase structure function of laser beam, the structure-function method for generating phase screens is presented, by which the Kolmogorov turbulence of different strength is numerically simulated to investigate its distortion on SAL imaging ability. By combining it with the rank one phase estimation (ROPE) algorithm, improvement of both accuracy and efficiency can be obtained by overcoming the weakness that ROPE is sensitive to initial value. Experiments show that the simulating results by structure function method, will be much closer to the theoretical value than that by spectrum method, and computational complexity will also be reduced from O(N2) to O(N). At the same time, image distortion induced by atmospheric turbulence within a certain intensity range can be restored by the modified ROPE algorithm. Compared with the traditional ROPE, compensation results by the modified method can have a 5 dB signal-to-noise ratio improvement, and computing time can be cut down by 30%.