<p>Traditional metal materials are unable to adapt to the rapid development of the marine engineering field. As an emerging material, high-entropy alloys have attracted much attention. In this paper, AlCrFe₂NiCuNb_x (<i>x</i> = 0, 0.25, 0.5, 1.0) high-entropy alloy surfacing layers were fabricated on the surface of carbon steel by GMAW . The effects of Nb content on the microstructure and corrosion resistance of AlCrFe₂NiCu high-entropy surfacing alloys were studied. The microstructure and phase composition of the alloys were characterized by using SEM and EBSD, and the corrosion resistance of the alloys was analyzed by means of an electrochemical workstation and XPS. The results show that the alloys are mainly composed of BCC, FCC and Laves phase. The microstructural morphology exhibits a typical dendritic and interdendritic structure. With the continuous addition of Nb elements, the self-corrosion current density of the polarization curve initially decreases and then increases, and the radius of the capacitive reactance arc of the impedance spectrum first increased and then decreased. When HEA-Nb_0.5 is reached, the self-corrosion current density is 0.71&#xa0;mA&#xa0;cm^-2, and the self-corrosion potential reaches − 385.36&#xa0;mV_SCE. The corrosion resistance of the HEA-Nb_0.5 high-entropy alloy cladding layer is the best. The Nb element is beneficial to improving the stability of the passive film and reducing the dissolution rate of the passive film. Excessive addition of Nb can lead to the precipitation of the second phase and lattice distortion in Nb-rich alloys. This can result in an increase in corrosion current density and the formation of more corrosion microcells, ultimately reducing the corrosion resistance of the alloy. It can be concluded from this that the addition of an appropriate amount of Nb can improve the corrosion resistance of the high-entropy alloy surfacing layer.</p>