A theoretical investigation is carried out in the field of the effects of the turbulent atmosphere on the laser beam. This thesis presents an analysis of laser propagation through turbulence which causes fluctuations of refraction index to have spatial power spectral density of refractive index, the contribution of log-amplitude and phase fluctuations. Kolmogorov turbulence is examined for plane wave of Nd:YAG laser. The spatial power spectral density of refractive index, the logamplitude and phase fluctuations, the covariance functions of log-amplitude and phase, the phase structure function, the variances of log-amplitude and intensity through turbulent atmosphere, the normalized covariances of logamplitude and intensity through turbulent atmosphere, the average intensity with and without turbulence are examined. The error of laser propagation through turbulent atmosphere are examined also by Strehl ratio. The log-amplitude and phase fluctuations, the covariance functions of log-amplitude and phase are computed numerically. The results are computed using computer program that is written by MATLAB 6.5.