The modal parameter of journal bearing is an important index for its condition monitoring,while the wear of the bearing surface,lubrication and working conditions have great influence on the modal parameters of the bearing.In order to monitor the operating modal parameters of the journal bearing effectively and realize the early fault diagnosis,the dynamic model of journal bearing was established and the modal parameters of the system were extracted by the method of complex modal analysis.The mechanism of high frequency vibration induced by the interaction between lubricating oil and bearing surface was studied.The effects of speed,load and lubricant viscosity on modal parameters were analyzed and verified by experiments.The results show that the lubrication of bearing has a great influence on high frequency vibration.When the stiffness of oil film is high,the mode order affected by lubrication is less,and the natural frequency is increased first and then decreased with the increase of rotation speed.The amplitude is increased with the increase of load in the high frequency band,while the modal frequency is decreased with the increase of the viscosity of lubricant in low frequency band.