The dissimilar metals of copper alloy and stainless steel are joined by single friction stir lap welding. Ni-based alloy coating with WC is deposited on the transition layer of stainless steel by laser cladding. Optical microscope (OM), scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), X-ray diffraction (XRD) and micro hardness tester are used to investigate the microstructure, phase and hardness. The results show that a reliable connection is formed in the transition layer of stainless steel and copper matrix, the homogeneous layers of stainless steel and copper are formed in the middle and lower part of the welded zone(SZ)； intercalations NiCu₄ are observed in the layered structure, for which untypically high hardness value 277 HV is registered; the microstructure of Ni-based alloy is compact and the coating is composed of γ-Ni，Ni₃Fe，WC，W₂C and Cr₂₃C₆. The average hardness of the coating is increased, which is 5.7 times as high as that of copper alloy.