Abstract: Attenuation for optical transmission through rain and the property of raindrop size distribution are reviewed. It is introduced and discussed both the scattering model and the non-scattering model. The latter model is discussed in length. Also by using a new and relatively accurate drop size distribution model it is calculated both the maximum distance that optical waves can penetrate through rain and the attenuation for light intensity.

Key words: laser transmission, terminal velocity, drop size distribution, maximum transmission distance, intensity attenuation