The low friction design of tapered roller bearings is crucial for enhancing the reliability of rotating machinery systems. However, under high-speed and heavy-load conditions, the elastic deformation of the rotor significantly impacts the bearing’s operational performance. To this end, this paper constructs the differential equations of motion for the bearing assembly and rotor system based on rigid body motion laws and finite element analysis methods. By real-time coupling of both systems, a bearing-rotor system dynamics model is developed, and experimental verification of the rotor system’s frictional torque is conducted to confirm the accuracy of the model. Based on this, the influence of operating conditions, unbalanced mass, and rotor structure on the dynamic friction characteristics of tapered roller bearings is investigated. The results show that the impact of unbalanced mass on the bearing’s frictional torque is affected by both the rotational speed and the eccentricity of the mass disk. When the rotor is unbalanced, significant differences in the frictional characteristics of the bearing supports exist on both sides.