Abstract: Aiming at the problem of excessive manual intervention of the existing cold rolling finishing unit, the control system and core database of the existing finishing unit were analyzed, and the technical scheme of automatic control and upgrading of finishing unit was formed. Secondly, the alternating control strategy of constant elongation and constant rolling force mode was determined, the automatic function of logic control and execution control module were improved, and the core database of the control system was expanded and refined. Finally, the process adjustment program of constant elongation and constant rolling force was optimized. The feed-forward preset parameters and the flatness feedback closed-loop control and adjustment mechanism of the finishing unit were established, and the automatic control function of the plate shape of the finishing unit was completed. This research is applied to the industrial production, and the automatic control function of the finishing unit based on the online data is realized. The automation rate of the unit increases to more than 90%, the manual operation and the scrap rate are reduced.