The temperature of the laser crystal in a solid-state laser can affect the performance of the laser, such as power stability and spot quality. A high-precision temperature control system has been designed to meet the temperature control requirements of crystals in solid-state lasers. The system adopts a non-equilibrium bridge combined with thermal sensors for temperature sampling, a second-order active low-pass filter to filter out high-frequency noise interference, and a high-precision ADC scheme to improve sampling accuracy. Two half bridge driving chips form a semiconductor cooler (TEC) driving circuit, which has strong driving ability. By improving the PID algorithm, the response speed is increased, and the working current of TEC is adjusted more quickly and accurately to achieve highprecision and stable temperature control effects. The GD32F103RCT6 microcontroller is used as the control core to build a temperature control system. The experimental results show that the system can achieve stable control within the set temperature range of ± 0.005 ℃.