Abstract: Based on shape and gauge decoupling design, coupling relations between crown control and flatness control were analyzed to establish crown and flatness coupling models for different shape control schemes, and the coupling characteristics were analyzed and compared. Crown and flatness semi-decoupling design was put forward according to the coupling models' characteristic. A crown and flatness decoupling control system and its application strategy for tandem cold mills were designed to accomplish a dynamic shape control system. After operating in a 1 420 mm 5-stand UCMW tandem cold mill, the dynamic shape control system approves good ability of improving shade and gauge control nreeision.