Abstract: Rectifying tower control system is a multi-variable control system with serious coupling among variables, and has many features such as nonlinearity, big lag time, large amount of random disturbance. It is hard to get an accurate mathematical model of rectifying tower control system and get satisfactory control effect by using traditional PID control. In view of above problems, the paper put forward a design scheme of rectifying tower control system based on fuzzy immune PID. It gave realization ways of hardware and upper computer software of the control system. The experimental result showed that fuzzy immune PID control has features such as smaller overshoots, shorter response time and smaller oscillation of transition process compared with common PID control, enhances accuracy, rapidity, stability and robustness of the rectifying tower control system, and greatly improves control effect.