Abstract: Based on the optical image de-rotation implemented by the transmission mechanism of a panoramic observation sight, the advantages and weaknesses of traditional optical de-rotation methods were analyzed. By simplifying the mechanism, the mathematical model of the controlled object was established. According to the system requirements of real-time controlling and processing, the digital-analog control hybrid circuits were designed, which improved the stability and reliability of the system. A typical instance of the control system was simulated with MATLAB/SIMULINK, the results show that the electric circuit can meet the requirements of stability and real-time processing.