As development of laser technology, the characteristic of laser atmospheric propagation is always hot spot in laser domain. Using theoretical models of laser atmospheric propagation, a simulation system is researched by implementing a scientific method of software development. This simulation system can simulate the radiate property of laser propagation in atmosphere, and demonstrate the course of laser propagation. This theoretical model of atmospheric propagation is based on Lambert-Beer law, combined with other classic theoretical model such as Rayleigh scattering and Mie scattering. Multiple scattering theories are used when simulating the laser propagation in smoke or fog. In calculation, the atmosphere is divided into layer. An appropriate model will be selected for calculation in each layer in order to enhance the stimulation precision. Lastly, the figure of light spot is drawn along with transmission space. Laser atmospheric propagation is demonstrated.