Abstract: Based on lubrication theory, 2D coupled equations of water film evolution and cable vibration are derived. This numerical model could be used to describe cables with an arbitrary 2D shape subjected to wind and rain. Cables with two ribs are analyzed by numerically solving the coupled equations. The vibration characteristics of cables, rivulets and aerodynamic lift are analyzed to investigate a possible vibration control mechanism of changing the surface shape of cables. The results show that although stay cables with two ribs cannot hinder the formation of upper rivulet compared with the case of circular cables, they could reduce the thickness of upper rivulet and impede the upper rivulet sliding around the cable periodically. Thus the frequency correlation between the water film and cable is disturbed, and the periodicity of aerodynamic lift is weakened. Therefore the large amplitude of cable vibration is suppressed and the resonance between the water film and cable does not occur.