This work is focused on the optical wireless links working in turbulent atmospheric transmission media. A phenomenon of atmospheric turbulence is briefly introduced and relative variance of optical intensity in laser beam profile is presented. The goal of this paper is to determine the distribution of optical intensity relative variance in laser beam profile. According to the experimental results we can say that this distribution is non uniform. It depends not only on the wavelength of used optical source, the distance between optical transmitter and receiver and the volume of atmospheric turbulence represented by refractive index structure parameter, but also on the angular coefficient of optical intensity profile.