The bistable behaviors of the rigid rotor with centralizing spring and squeeze film damper are studied by means of calculations and experiments. The bistable behaviors are characterized by the variations of eccentricity
transmissibility and Lagging phase angle. The results calculated and experimental data are in a good agreement. The bistable operation of the rotor canbe eliminated at operating speeds if only the bearing parameters including the length and clearance of the film damper
and the stiffness of the centralizing spring are chosen properly over a certain unbalance range of the rotor.