Abstract: In consideration of the cubic nonlinear spring and spring static deformation, the dynamic control equations of second order nonlinear system were established for the mechanical model of driving point anti-resonant vibrating machines. The condition of the system producing internal resonance was obtained and the average equation was established with the multi-scale method. Moreover, the effects of different structural parameters on the nonlinear dynamics characteristics were studied. The results showed that the influence of nonlinear can be ignored when the exciting force frequency is smaller than the anti-resonant one, on the contrary, the influence can be enhanced and the amplitude appear bifurcation which becomes larger with the increasing difference between exciting force and anti-resonant frequency.