A dynamic model of the sliding bearing-rotor system under the conditions of misalignment, rubbing and unbalance was established, and a series of strong nonlinear couplings such as misalignment, sliding bearing oil film force, turntable eccentricity and rubbing were comprehensively considered. Using the fourth-order Runge-Kutta numerical integration method in the C language environment, the analysis method of the collision oscillator system was introduced to analyze the rubbing bifurcation transition behavior of the rotor system, and the maximum rubbing force and duty cycle were introduced at the same time to quantitatively characterize the system response caused by the parameter change of the rotor model. The research shows that the misalignment fault causes the rotor system to generate even multiple frequencies such as 2× and 4×, and the amplitude of the 2× frequency does not change with the change of the speed and system parameters. Changes in bearing clearance and lubricating oil viscosity have a significant impact on the system response, which is manifested in the fact that the stability of the system increases with the reduction of bearing clearance and the increase of lubricating oil viscosity, especially the increase of lubricating oil viscosity makes the system critical speeds of the first and second order increase significantly.