Abstract: Bearing is the only dynamic-static contact component of the flexibly supported rotor. The dynamic response characteristics of the rotor are related to the friction between the bearing and fossa. Therefore, it is of great significance to study their mechanism and influencing factors for the design and optimization of the bearings. In order to study the influence of the bearing friction and wear on the dynamic response characteristics of the rotor, the nonrigid connection model of the bearing was established and introduced into the rotor system. The influence of bearings with different degrees of friction and wear on the dynamic response of rotor was studied theoretically. The response characteristics of the rotor under the condition of bearing friction and wear were calculated and analyzed. The maximum energy released when the rotor precession failure was caused by bearing wear was analyzed. The results show that with the increase of bearing friction and wear, the amplitude of the rotor vibration increases, and the second order precession phenomenon appears. In severe cases of wear, quasi-periodic motions also appear. Bearing friction and wear may lead to different failure modes of the rotor. When the rotor conducts the secondorder precession and a quasiperiodic motion, the maximum energy released by the failure rotor will be greatly increased. The research results could provide a theoretical basis for the optimal design of bearings.