Abstract: Aiming at the strong coupling and nonlinear vibration problems of the twenty-high rolling mill during the production of ultra-thin strips, this paper establishes a six-degree-of-freedom nonlinear dynamic model for the working roll-first intermediate roll. Considering the nonlinear stiffness and damping at the rolling interface, the amplitude-frequency characteristic equations of primary resonance and internal resonance were solved by the multi-scale method, and the influence of different parameters on the amplitude-frequency characteristic curves was analyzed. A tuned mass damper was designed to control the nonlinear vibration characteristics of a twenty-high rolling mill, and a coupled dynamic model of the tuned mass damper and the rolling mill system was established. The influence of mass, stiffness and damping ratio on the dynamic amplification factor of the rolling mill was analyzed. To minimize the peak value of the dynamic amplification factor, the parameters of the tuned mass damper were optimized by the adaptive genetic algorithm, and the optimal mass, stiffness and damping ratio were determined. Finally, the feasibility and effectiveness of the TMD controller were verified by simulation comparison using time-domain diagrams, phase diagrams, frequency spectra and Poincaré section diagrams, which has important guiding significance for real production.