In the photoelectronic tracking system, The ability to capture and trace is determined by the tracking precision of servo system. As the photoelectric tracking servo system gradually rise to the requirement of tracking precision, repetitive control technology is introduced into the servo system in this article, repetitive control technology not only can realize high-precision tracking, improve system performance, and can track the periodic signal. In this paper, optimization of plug-in repetitive controller was designed, to track the equivalent sine signal, the simulation results show that the tracking error of repetitive control system is obviously decreased, and its tracking accuracy is improved obviously compared with commonly used high precision control method.