In order to control the vibration, a term of displacement feedback was introduced to the bearingrotor system with oil film force. The nonlinear dynamics behaviors of the controlled system with different groups of parameters (dimensionaless eccentricity and a comprehensive parameter, which mirrors many factors such as rotor weight, viscosity of lubricating oil and freegap in the bearing)were analyzed by the help of bifurcation diagram and ｐoincare mapping. The results show, with a small feedbackgain (less than 1), that the complicated motioncan be converted into a simple periodic motion. And the method given in this paper is easy to be applied to experiments, for only one variable is to be controlled.