Abstract: Al_xFeCrNiCoCu (x=0, 1, 2, 3) high-entropy alloy coatings (HEAs) were prepared by spark plasma sintering. The effect of Al content on microstructure and erosion wear resistance of Al_xFeCrNiCoCu high-entropy alloy coatings were studied by x-ray diffraction, scanning electron microscopy and erosion wear tests. The results show that the coating microstructure was mainly composed of a Cu-rich phase and an Al-rich phase with simple FCC solid-solution structure. With the increasing Al content, the microstructure evolved gradually from FCC to BCC. And the hardness and erosion resistance of the HEA coatings were increased significantly. The mass loss rate of HEA coating increased with the increase of erosion angle, exhibiting an erosion characteristic of brittle materials. The domain erosion wear mechanism of the HEA coatings changed from micro-cutting and forging extrusion to ploughing with the increasing Al content.