Abstract: Copper gradient layer was prepared on the surface of carbon steel by electrodeposition-diffusion method, and the copper/carbon steel gradient material was obtained. The effects of copper diffusion and heat treatment on the microstructure and mechanical properties of carbon steel were studied by metallographic microscope, scanning electron microscope, Vickers hardness test and three-point bending test. The results show that copper diffuses mainly along grain boundaries in carbon steel, and the diffusion of the copper also limits the growth of the carbon steel grains in the high-temperature process. Copper/carbon steel graded material prepared by annealing diffusion has a hardness and flexural strength close to that of carbon steel. With the increase of the depth of copper diffusion layer, the surface Vickers hardness and bending strength of carbon steel/carbon steel gradient materials containing copper increase gradually.