Abstract: Continuous model of rotor-bearing system with double diskssupported by cylindrical bearings is analyzed in this paper. Shooting methodis used in the stability analysis of the continuous system. Therotor-bearing system with double disks is analyzed by considering the diskeccentric magnitude, eccentric initial phase, bearing clearance, dynamicviscosity of the oil and bearing aspect ratio. Some useful conclusions arefound: instability is mainly caused by the period-doubling or quasi-periodbifurcation; instability speed can be increased by decreasing the diskeccentric magnitude or increasing the initial eccentric phase difference ofthe disk; increasing bearing aspect ratio and decreasing bearing clearanceproperly can inhibit the instability occurring early; the higher dynamicviscosity of the oil is not the better, otherwise oil with lower dynamicviscosity can increase the instability speed properly. Research method andconclusions in this paper can provide theoretical reference for thestability design and vibration control of the more complex rotor-bearingsystem.