A rolling force model of continuous cold rolling mill based on elastic and plastic mechanics was developed and successfully applied in the control system of a 1420 mm cold rolling mill in Baosteel. Considering simplicity and practicability of calculation, stress of elastic zone and plastic zone during the cold rolling process was calculated and analyzed by incorporated simple finite element method and recursive calculating method. Compared with the measured rolling force, the results of the rolling force model are beyond 96.5%. A method for optimizing rolling force by improving reduction, dimension, coefficient of friction, deformation and tension is put forward.