Abstract: Aiming at the problem of atmospheric attenuation and intensity fluctuation of the field operations wireless laser communication, the effect of atmosphere on laser communications was analyzed, the suppressing mechanism of the atmosphere adverse effects using multi-caliber-launching and large-caliberreceiving was explored on laser communication. A multi-caliber-launching and large-caliber-receiving test device was built. The number of emission caliber was adjustable on emission end, and the Cassegrain structure was used in optical antenna on receiving end. The antenna caliber could be changed by adding different calibers apertures in front of optical antenna. When the number of emission caliber was increased to 4 beams, the value of light intensity fluctuation variance was about 1/2 of the single beam. And with the receiving aperture diameter difference of 1.5 times, there was a 1.6 times difference between scintillation variance. The multi-caliber-launching and large-caliber-receiving inhibitory effect of atmospheric turbulence was validated by experiments. According to the test results, some parameters of laser communication terminal of were optimized.