As development of laser technology, the characteristic of laser atmospheric propagation is always hot spot in laser domain. Integrating Lambert-Beer law of laser atmospheric propagation, combining Rayleigh scattering and Mie scattering, a simulation system is designed. This simulation system can simulate the course of laser propagation in complex atmosphere. In order to obtain the final optical field through the atmosphere turbulence, the random disturbance could be simulated by a series phase screen which is based on Fourier transform. Lastly, the figure of light spot is drawn along with transmission ranges.