Semiconductor lasers have very strict requirements for operating temperature, and the threshold current, output optical power and wavelength of semiconductor lasers will change dramatically with the change of temperature. In order to ensure the normal operation of semiconductor laser, a temperature control circuit based on single chip microcomputer is designed, which includes temperature acquisition circuit composed of current source and instrument amplifier chip and thermoelectric cooler (TEC) drive circuit composed of power chip. Two pulse width modulation signals with different duty cycle are output by proportional-integral-differential (PID) algorithm to control TEC drive circuit. A method of reducing the pulse width modulation signal frequency to improve the output voltage modulation accuracy of TEC drive circuit is proposed to improve the circuit temperature control performance. The temperature control circuit of semiconductor laser based on STM32F103CBT6 is built to verify the feasibility of the experimental method. The experimental results show that when the ambient temperature is 20~50 ℃, the circuit can realize the stable control in the set temperature range of ±0.01 ℃.