Based on the laser melting deposition technique, the TC4-Cu duplex coating is prepared with A3 steel as the matrix, copper alloy as the transition layer and TC4 alloy as the coating. The interface structure, chemical compositions and phase compositions are analyzed. Meanwhile, the microhardness and the corrosion resistance of this coating are tested. The results show that the atom diffusion occurs at the TC4-Cu-Fe interfaces. Solid solutions, like α-Fe and α-Ti, are formed at the interfaces. The grains in the binding area have small sizes. The Ti diffusion to the Cu-Fe interface is blocked by the transition layer successfully. The average microhardness of the coating is about 500 HV, which is about 3 times of that of the matrix. The corrosion resistance of the TC4-Cu duplex coating is slightly higher than that of the commercial TC4 alloy, and far higher than that of A3 steel.