With industrial equipment advancing toward high-speed, heavy-duty, and high-precision applications, cylindrical roller bearings (CRB) are increasingly subjected to substantial axial loads under complex operating conditions, while existing research still shows deficiencies in analyzing their axial load-bearing characteristics. Building upon elastic contact theory, tribology principles, and hydrodynamic lubrication theory, this study develops a quasi-static mechanical model for CRB under combined radial-axial loading conditions. Furthermore, an enhanced local calculation method for determining bearing friction torque is proposed. Experimental verification demonstrates that the model can accurately predict the frictional behavior of bearings under combined loading conditions. Through systematic integration of theoretical analysis and experimental testing, this research comprehensively investigates the influence patterns of key operating parameters on the dynamic friction characteristics of bearings. The results reveal that, compared to radial and axial loads, the rotational speed of the inner ring exhibits a more significant impact on the bearing's friction torque. The proposed research methodology establishes a theoretical foundation for friction-optimized design of CRB under combined loading conditions, providing substantial engineering significance for enhancing the service performance of high-precision bearings.