Semiconductor lasers are widely used in many fields, such as industry, medical treatment, scientific research, information, and military. Because the output wavelength and power of semiconductor laser will change significantly when the working temperature of semiconductor laser changes slightly, a high stability constant temperature and constant current driving power supply for semiconductor laser is developed in this paper. A constant current source consist of a field effect transistor and an operational amplifier is used for providing a high-precision and high-stability input current for that laser; a slow starting circuit is designed to protect the semiconductor laser and avoid the damage to the semiconductor laser caused by the peak and overshoot of the output current waveform of the power supply during starting. The MAX1978 chip is used to perform PID operation on the deviation between the real-time working temperature collected by the thermistor and the preset temperature, and the TEC is controlled to refrigerate or heat so as to realize the long-term stability of the working temperature of the semiconductor laser. The test results show that the output current of the power supply is continuously adjustable from 0 to 100 mA, the current accuracy is 0.01 mA, the control temperature accuracy is 0.01 ℃, and the power is stable for a long time. The power supply has the characteristics of good real-time adjustment performance, low cost, and easy implementation.