Abstract: Inner parameters and outside load of operating-side and drive-side subsystems of a cold rolling mill are different and uncertain, which can lead to different dynamic and static performances and asynchronous pressing down positions. Consequently, strip thickness of the two sides and the quality of strip shape are impacted. To solve this problem, the synchronous closed loop controller is necessary in the position control system of both sides of the cold rolling mill. A robust dynamic output feedback synchronous controller is designed for the pressing down position system with uncertain parameters and outside load disturbance. And the stability of the designed control system is proven in theory. The results of simulation and experiment research are given to illustrate the effectiveness of the proposed synchronous controller.