The characteristics of laser transmission in atmosphere are an important issue that must be considered for applications in laser engineering. For 1.06 μm and 10.6 μm laser, the single scattering parameters of aerosols are calculated based on the Mie scattering theory. For the transmission attenuation of the laser in aerosol, the Monte Carlo simulation model is established. For dust-like, water-soluble, oceanic and soot four types of aerosols, the relations of transmittance to visibility and propagation distance are computed and analyzed using the program written in MATLAB language respectively. The results show that single scattering calculation has a larger error when the visibility is low, and albedo is high. Using the Monte Carlo method to calculate the attenuation of the laser transmission in aerosol can reveal multiple scattering phenomenon. For the 1.06 μm laser, the attenuation capacity of soot aerosol is strongest, and for the 10.6 μm laser, the attenuation capacity of dust-like aerosol is strongest.