Abstract: The wheel-side reducer, as a critical component of the loader's transmission system, requires accurate analysis of its contact model to ensure structural reliability, fatigue life and transmission efficiency. In this study, Hertz theory was employed to solve the contact problem between a pair of sun and planetary gears, while finite element analysis of gear contact was conducted using Workbench software. The results indicate that the Hertz model exhibits significant errors in contact stress calculations due to its neglect of tooth surface plastic deformation, excessive conditional assumptions, and model simplifications, though the error in the actual contact area remains moderate. In contrast, the finite element model considers factors such as material nonlinearity and friction during simulation, yielding relatively more accurate contact stress results compared to the Hertz model, albeit with larger errors in the computed contact area. The findings of this study provide a basis for further research on gear contact modeling.