Abstract: With the increasing demand for low energy consumption in equipment, such as new energy vehicles and wind power equipment, the low-friction design of their tapered roller bearings has became increasingly important. Two characteristics of tapered roller bearings have greatly hindered the investigation of their friction properties. One is the structural feature that the center of the entire bearing does not coincide with the center of each component, and the other is the coexistence of rolling and sliding friction states due to the intermittent contact of the components. To this end, based on the local friction features inside the bearings, its frictional torque model is developed with the combination of dynamic and fluid lubricant theories. A variety of lubrication states are considered in it. In this process, the rolling friction of the raceway and the sliding friction of retaining edge were firstly modeled. The contact parameter at each contact interface was obtained from Hertzian theory. Considering the lubricant rheology, the interface friction states were further derived using state assessment model. On this basis, the dynamic model of tapered roller bearing was finally developed and the values of each friction source inside bearing were extracted. Some experiments on the bearing frictional torque were carried out to verify the friction model. In the test rig, the product between the rotational resistance of the two rings and the force arm was used as the test torque of the tapered roller bearing. A good agreement between the test results and predictions of the model was observed (error not exceeding 6%). Finally, based on the presented model, the friction characteristics of tapered roller bearings under typical working conditions were investigated. Some interesting conclusion could be drawn as follows: while an increase in driving speed improved the lubricant at the interface, it also significantly increased its hysteresis effect leading to the overall bearing frictional torque; compared with the rotational speed, the interface lubrication state was less affected by the load, and the bearing component interaction force showed a linear relationship with the axial load, while the radial load disturbed the stability of the friction moment in the time domain. This work provided support for low-friction design of tapered roller bearings.