Abstract: Based on the extended Huygens-Fresnel integral, the cross-spectral density and Rytov's phase structure function, average intensity was derived by a formula for the Fourier transform of Gaussian function. Then mean squared root beam width, beam wander of a partially coherent Gaussian-Schell-model (GSM) beam in turbulent atmosphere were found out. It shows that beam spread and beam wander have relation with initial beam radius, initial coherence width, wavelength and transmitter hight in the atmospheric turbulence. At last, some measures were brought to decrease the effect of atmospheric turbulence.