To improve the corrosion resistance of 316L substrate and extend its service life in marine environment, Ni-Cu-WC cladding layers with different copper content were prepared on 316L stainless steel by laser cladding technology. The microstructure, hardness, corrosion resistance, and corrosion behavior of the cladding layer were analyzed by scanning electron microscope, energy dispersive spectroscopy, microhardness tester, and electrochemical workstation. The results show that the coating has good forming quality, and the dendrites of the cladding layer is induced by excessive Cu addition. The addition of Cu partially inhibits the formation of carbide reinforcing phase, resulting in a decrease in the hardness of the cladding layer. At the same time, the Cu element in the cladding layer can effectively improve its corrosion resistance in seawater. The experimental results show that the corrosion resistance is the best when the mass fraction of Cu is 0.1, the corrosion potential increases to -0.864 V in the NaCl solution(mass fraction of 0.035), and the corrosion current density decreases to 0.1049 μA/cm2, respectively. This study provides a theoretical reference for the preparation of seawater corrosion resistant coatings by laser cladding.