Abstract: A complex coupling model for wide strip tandem cold mills was established based on systematic analysis on the factors affecting on shape, gauge and tension. Aiming at the characteristics of the model, ordinal decoupling design was put forward which could simplify decoupling process more explicitly than normal decoupling design, and the simplified method of decoupling channels was given for practical application. Based on actual rolling parameters of the first stand of a 1250 mm 8-high 5-stand tandem cold mill, the ordinal decoupling system after simplified was analyzed by Matlab/Simulink tools, and the results show its decoupling effectiveness.