The suntracking control system enables received surface of the solar optics always perpendicular to the incident light, which can significantly increase energy received of the solar thermal power generation system, greatly improve the power generation efficiency of solar power generation systems. This paper presents a dualaxis sun tracking control system based on STM32, which can switch the solar trajectory tracking control method and the photoelectric tracking control method automatically according to the lighting conditions , and adjust the motor rotation to complete accurately the position of sun around the clock tracking. Test shows that the sun position accumulated error value of the dualaxis tracking control system is less than 2 degrees per hour. The system basically meet expectations, and has a higher practical value on solar thermal products.