The study on laser transmission and scattering characteristics in complex environments is the basis research of light scattering from target and environment. The severe attenuation caused by laser propagation in sand and dust storms was mainly discussed in this paper. The attenuation characteristic of laser was studied with Mie theory for single scattering of sand and dust particles with special size distribution. Based on Mie theory, the average scattering cross section, albedo, asymmetry factor, and phase function were calculated. The laser multiple scattering and attenuation characteristics of slanting transmission in the layering sand dust atmosphere were studied by using four-flux model method and Monte-Carlo method, and the relationship between attenuation and visibility in difference heights was also given. Finally, after considening of multi-scattering, numerical calculations of specify attenuation were made for laser signal of 1.06 μm in sand and dust atmosphere by using the above two methods respectively, and the results were compared to the condition of single scattering. It is shown that biggish error can be brought in the low visibility take no account of multiple scattering, and that the more layers of the sand and dust atmosphere is divided into for slanting transmission, the more accurate the result is.