In order to overcome the shortcomings of traditional finishing machines, such as low automation degree, bad reliability and more failures, the automatic control system for finishing of precise flat steel is developed based on PLC, touch screen and invert in this paper. The producing flow and control requirements of finishing precise flat steel are introduced. The control system is used to adjust the speed of equipment for finishing precise flat steel. Application of touch screen offers a better HML By adopting semi-closed control strategy response time is reduced and control accuracy is improved. The system has good effect in practice.