The paper aims to study the dynamic behavior of the nonlinear vibration isolation system. Influences of damping coefficient and dimensionless parameter R on the magnification of the cubic nonlinear system were studied, and the isolation design was carried out. The magnification peak decreased with the increase of damping coefficient and dimensionless parameter R. The nonlinear behavior of the system was conducive to the isolation performance of the system. Even if the damping coefficient equals zero, there will be no infinite magnification; the increase of the system damping is conducive to the improvement of the isolation performance.