A dynamic model of seven degree of freedom for the vertical vibration of stand rolls system in a cold tandem mill is developed by Kinematics Theory. According to the actual parameters of a factory six-roll cold rolling mill, the influence of natural frequency and modes for rolling process is analyzed. It finds that the third-order and the six-order natural frequency play a role key in vertical vibration system. Combined with energy distribution of each part and flexibility of the modes analysis for vertical vibration system, it can avoid resonance of rolling process and optimize the parameters of stand rolls system by adjusting structural size appropriately. The above mentioned results have provided a reference for further research on Kinematics and structural optimization of six-roll cold tandem mill.