Abstract: The distributed rules of some rolling factors such as tension and friction stress in the strip transect along the rolling direction as well as the relationships between these factors and strip thickness were discussed by discretization of the rolling deformation zone. The metal deformation resistance was calculated by a mathematic model with the ANN technique. An online calculation model of rolling force was setup for a tandem cold rolling mill. Experimental data of a huge industrial rolling mill showed that the errors of the predict model were less then 6.1%. It is concluded that this proposed model can meet the requirements of online control and improve the online calculated precision of rolling force.