Abstract: To examine the effect of the non-spherical raindrops on laser transmission attenuation in atmospheric, based on the approximate ellipsoid model of raindrops and normalized raindrops size distribution, the scattering characteristics of raindrops cluster in the visible and infrared domain were calculated by ray-tracing method. The effects of raindrop size distribution and rainrate on the laser transmission attenuation were discussed. The numerical simulation results show that the scattering capabilities of raindrops cluster decrease in the order of JD, MP, Gamma and JT; the laser transmission attenuation are not only affected by the rainrate, but also affected by number density of rainfall, the more the raindrops, the stronger the laser transmission attenuation; while the effect of shape of raindrops is relative small. These results will be benefit to evaluate the effect of precipitation on laser transmission, which will promote the application of laser signal transmission, communication and wind measurement by laser.