In the laser communication, semiconductor laser is the most common light source device, which has a great influence on the performance of the whole system. The nonlinear model of the laser was modeled, then the linear method and the mapping function of the semiconductor laser were discussed. Finally, the I-V characteristic curve of the laser was obtained according to the actual working conduction. Based on the Volterra series theory, the nonlinear model of the cemiconductor laser was established and the three polynomial coefficients were obtained. The method of predistortion compensation was designed to correct the nonlinear effect of laser, and the validity of the method was verified by experiments.