In order to investigate the transient nonlinear dynamic behavior in connection to the contract between the auxiliary bearing and magnetic rotor under high-speed rotation,bifurcation diagrams,time responses,Poincaré sections and phrase diagrams are synthetically employed in the present article based on the numerical integration method. Firstly,the respective effect of geometric coupling parameter α,proportional feedback gain P and derivative feedback gain D on the system is explored. Then,the impact of stiffness ratio K and Coulomb sliding friction coefficient μ on unbalanced parameter U are also discussed respectively. The results show that when the value of geometric coupling parameter α is large,it can lead to the offset of the rotor from the equilibrium position,corresponding to the rub-impact phenomenon of the rotating rotor and auxiliary bearing so that the equipment is disturbed by the abnormal vibration,however,either the large value of proportional feedback gain P or derivative feedback gain D can be in connection with the stable state of the system. In addition,the softly mounted auxiliary bearing is beneficial to the stability of the system,and the choice of unbalanced parameter U has a significant effect on the state of the system.