Abstract: There has been lacking of general simulation tools for complicated laser system in China for a long time. In order to solve this problem, we have built the component-based laser system simulation software called EasyLaser, which is based on the credible modules accumulated by many years and is very easy to use. It is composed of a general modeling and simulating platform called SciSimu and eight component libraries for simulation. It has the ability of modeling and simulating some complex processes, such as the beam propagation between the optics, the beam propagation through the atmosphere, the optical imaging, the adaptive optics correction, the recognition and tracking process, etc. The simulation ability and software feature of EasyLaser is introduced in detail in this paper. In addition, a simulation model is built by EasyLaser to analyse the correction effect of the adaptive optics system for the atmosphere turbulence.