Abstract: Finite-element method was used to simulate the nano-indentation and nano-scratch tests.The hardness and frictional behaviors of the epoxy/polyurethane functional gradient coatings with different thicknesses on Q235 steel substrate were comparatively investigated.The results showed that thickness palyed an important role in the properities of coating.The 5.5 μm coating had better propertices than the 11.0 μm and 22.0 μm coating.For the coating with different thicknesses of 5.5 μm,11.0 μm and 22.0 μm,the hardness was 45.6,36.4 and 29.3 GPa and the friction coefficient was 0.024,0.036 and 0.057,respectively.Coatings with thinner thickness had better wear-resisting properties.