The modified layers were prepared on the surface of 40Cr samples by two composite processes of plasma nitriding followed by laser quenching and plasma nitriding followed by laser quenching, the phase characters of the modified layer were analyzed by microhardness, metallographic and x-ray diffraction, the electrochemical and friction experiments were carried out to compare the surface properties. The results show that the surface of the post-laser quenching process consists of α′ phase, low nitrogen compounds and oxides which are mainly composed of Fe3O4, the surface hardness is 818 HV, the thickness of the modified layer is 1 100 μm, the hardness gradient is gentle, and the wear resistance is better. The surface of the post-plasma nitriding process is mainly composed of γ′-Fe4N and α′ phases, the surface hardness is 970 HV, the thickness of the modified layer is 500 μm, and the corrosion resistance is better. Different phases of the modified layers by two composite processes lead to differences on the corrosion and wear resistance, and the composite process should be selected according to the working conditions.