The original control system adopts MEH controller and maintains the operation of the unit by continually backflow. But surge problem still exists in the running, which constitutes a serious threat to the safety of the unit, meanwhile wastes a lot of energy. Later S5 Duplex control system of CCC Company is adopted in the reconstructed control system, which rebuilds the compression anti-surge control system, eliminates surge threat and huge energy consumption. Millions of profits can be created by this renovation each year. The targets of stable operation and energy conservation can be achieved as well.