Using phase-screen approximation, the field distribution of laser beams propagating through atmospheric turbulence is calculated and simulated. The wavefront phase of the distorted beam in turbulence is also analyzed in terms of the high-frequency phase proportion and the number of branch points. Furthermore, considering the coupling between deformable mirror actuators, the model for estimating the physical limit of phase correction is built up by using the method of high-pass filtering including a smoothing factor of mirror actuator. The influence of turbulence intensity and propagation distance on the physical limit of phase correction is analyzed quantitatively. The results show that in a certain range, the proportion of high frequency in distorted phase increases obviously and the number of branch points grows gradually with the increase of turbulence intensity and propagation distance; the correction effect of laser beams in turbulence would be influenced mainly by the proportion of high-frequency in distorted phase and the number of branch points, and the greater the proportion of high frequency phase or the more the number of branch points is, the worse the correction effect of adaptive system would be.