Abstract: Temperature was one of the parameters influencing the characteristic of the semiconductor laser. To realize the temperature control quickly and stably, the temperature controlling hardware and algorithm were researched. The system was based on the Micro Control Unit(MCU) MSP430. The driver circuit was used, adjusting circuit voltage adaptively was in conjunction with output style of pulse width modulation. The self-adjusting temperature algorithm was also designed by the model of the mechanical temperature balance and experiment in high-low temperature test-box. According to the experiment result, the stability time from the temperature -40-+50 ℃ to the setting temperature 23 ℃ were respectively 2 min 30 s and 1 min 30 s, respectively. The control precise was 0.2 ℃. By the analysis of power stability experiment result, the laser power stability is improved from 5% before temperature control to less than 1% after temperature control. The laser power stability density is safe for the eye. The schematic design of system has significance for the small power and quick stability laser system.