Abstract: The dynamics equations of main drive system of a two-mass rolling mill with nonlinear damping and nonlinear stiffness are established under the action of impact moment. The stability of system is analyzed, and the influence relations among damping and stiffness with the stability of system are given. The system’s first-order approximate solution is obtained with the aid of multiple time scales method, so the torsional vibration responses of system are obtained. By means of simulation, the influences of nonlinear damping and nonlinear stiffness of shafting on vibration responses of the rolling mill’s drive system are discussed. Finally, the methods of impact vibration reduction of rolling mill are found. The research results provide theory basis and reference for restraining torsional vibration of rolling mill caused by impact disturbance.