The rough surface of sliding bearing was simulated by means of the fractal theory,and the influences of surface morphology on film thickness,pressure and capacity were investigated.Further simulations were performed on the anisotropic rough surface,and the tribological properties of bearing in circumferential direction were compared with the one in the axial direction.The results indicate that under a certain load,the smaller the fractal dimension,the larger the amplitude of surface profile;the simpler the surface profile,the more difficult the formation of lubricating film.The surface profile amplitude has a significant influence on lubrication film pressure,the greater the amplitude,the more smooth the pressure distribution of lubrication film and the worse the lubrication performance.The greater the surface characteristic roughness value,the lower the bearing capacity and the greater the friction.The influence of fractal dimension and characteristic roughness on the tribological properties of bearing in the circumferential direction is larger than that in the axial direction.