In the modulating retro-reflector (MRR) communication system, the influence of the atmospheric turbulence on the system is more serious than that of the traditional FSO communication system. In this paper, in order to reduce the impact of the atmospheric turbulence, an improved scheme based on the diversity of the retro-reflector is proposed. Using the power spectrum inversion method, the atmospheric propagation model of MRR under weak turbulence is established. The influence of the atmospheric turbulence on the retro-reflector diversity system and the traditional MRR communication system is compared and analyzed. The results of the numerical analysis show that under the same condition, the retro-reflector diversity of modulating retro-reflector (MRR) communication system can reduce the scintillation index caused by the atmospheric turbulence.