To explore the lubrication characteristics between the contact surfaces of the main bearings of RV reducer under the condition of elastohydrodynamic lubrication(EHL), a numerical model for point contact EHL of main bearings is proposed based on the non-Newtonian characteristics of grease and the fractal theory of rough surface. Firstly, the model is numerically solved to obtain the distribution of grease film pressure and grease film thickness. Then, the model is compared with the numerical results and experimental results of other point contact elastohydrodynamic lubrication models to validate the accuracy of the proposed model. Finally, the effects of rheological index, fractal dimension, entrainment velocity, load and grease viscosity on the lubrication performance of the main bearing under smooth and rough conditions are analyzed. The research shows that the more obvious the non-Newtonian property of the grease, the smaller the thickness of the grease film is and the less obvious the necking phenomenon. The pressure of the grease film near the contact area is more consistent with the Hertz pressure distribution, and the secondary pressure peak gradually disappears. Considering the elastohydrodynamic lubrication characteristics of the fractal rough surface of the main bearing is more realistic. Increasing the fractal dimension increases the real contact area of the contact area, which is beneficial to reduce the pressure of the grease film and increase the thickness of the grease film. The entrainment velocity, load and grease viscosity have significant impact on the thickness distribution of the grease film, while their influence on the pressure distribution of the grease film is comparatively smaller. Larger grease film thickness and the minimum film thickness contribute to the resistance of grease film breakdown and promote het formation of hydrodynamic lubrication.