A brief introduction of an optic-electronic tracking system using a fast reflection mirror is presented, the design of the fast reflection mirror control system, based on immune genetic PID algorithm, is described. Besides the ability of a stochastic global searching of simple genetic algorithm, the immune genetic algorithm used involves mechanisms which exist in biological immune systems, such as antigen memory, antibody encouragement and restraint, antibody diversity keeping, etc. By combining an algorithm of biological immunity with a genetic algorithm, a kind of optimal computing model is proposed based on a genetic mechanism of immunity. Taking immune genetic algorithm as a base, the optimal parameters of a PID controller are obtained. The simulation results of an immune genetic PID algorithm for the tracking system using a fast reflection mirror are presented, which show that the fast reflection mirror control system based on an immune genetic PID algorithm possesses superior qualities, indicating good prospects of application.