Abstract: The dynamic model of bearing rotor sealing system is established by applying transfer matrix method with the rotor of centrifugal fan taken as an object. The calculation method for contact rigidity, film rigidity and film damping of lip seal is constructed. The natural frequency, attenuation coefficients and modal shape of bearing rotor sealing system’s vibration are calculated and analyzed, as well as the influences of eccentric of impeller and belt wheel on the unbalance response amplitude of the system. The effect of interference of lip seal and shaft eccentricity on the vibration performance of bearing rotor sealing system is studied. The research of this manuscript can provide theoretical basis on the dynamics performance of bearing rotor sealing system.