The acting force on the roll system of Sendzimir mill was analyzed using 3D FEM. The roll gap pressure distribution and the acting force between rolls S and O, rolls O and I, rolls O and J, rolls I and A, rolls I and B, as well as rolls J and B were analyzed. The results showed that the roll gap pressure mainly affected the roll surface layer, 50 mm for backup rolls the roll gap pressure distribution is of double peaks among the work roll, the 1st intermediate roll (IMR), and the 2nd IMR; the maximum value of the roll gap pressure between the backup roll and the second IMR appears on the edge of the barrel of rolls; the component force presents the in-para-curve distribution. These are important for reducing the wear of rolls and the break of the backup roll and guiding for production. © 2008 Central Iron and Steel Research Institute.