Abstract: On the basis of Kolmogorov theory,the physical meaning of beam correlation function on receiving plane is extended.Based on the correlation analysis of multiple beams crossing over the atmosphere.The analytical solution formula of the light-intensity oscillation variance of multiple beams is deduced.The result shows along with the spacing increase of channels,the channel correlation decreases,and so does the oscillation variance.When the channels overlap completely,the light-intensity oscillation variance of multiple channels is no difference from that of one channel.