A high-precision digital temperature-control system (HPDTCS) based on TMS320F28069 for all-solidstate single-frequency green laser is designed and built. The speed-change integral PID control algorithm and the high-resolution pulse width modulation (HRPWM) technology are utilized in this system to control the drive current of the thermoelectric cooler (TEC). Depending on the difference of the temperature efficient of the thermistor under higher and lower temperature, the different temperature detection circuits are applied. The HPDTCS consists of three lower (10 ℃ to 40 ℃ ) and a higher (120 ℃ to 160 ℃ ) temperature- control modules with precisions of ± 0.0045 ℃ and ±0.005 ℃, respectively. Applying the HPDTCS to control an all-solid-state single-frequency green laser, the power fluctuation of ±0.33% is achieved at the output power of 11.07 W.