For the influence of the temperature and current, the power of semiconductor laser fluctuates constantly. So this paper comes up with a new method to solve this problem. The design of peripheral circuit contains two parts: temperature control and power control. The system of temperature control uses special laser temperature control chip, which realizes the accuracy of 0.01°C. The system of power control adopts hardware PI control, over-current protection, over-voltage protection, and temperature protection. Temperature compensation is added to the circuit, which realizes the accuracy of 0.01mW.