Based on single-mode rate equations of semiconductor laser,the typical parameters are used to model and simulate the semiconductor laser.The simulation results show that the initial photon stimulated emission rate of the semiconductor laser increases with the increase of the injection current,the rise time reduces with the increase of injection current.But for a fixed power limited semiconductor laser,the rise time can′t be reduced by directly increasing the injection current.Considering the heating problem of semiconductor laser,a method of adding an impulse current in the front of the normal luminous pulse current to reduce the rise time of the transmitted pulse of the semiconductor laser is proposed,which ensures the stable output of the semiconductor laser.The method is verified by simulation,and the PLTB450B semiconductor laser is tested.The simulation results and test results show that the rise time of the transmitted pulse of the fixed power semiconductor laser can be greatly reduced by adding impulse current.