FeCrNiCoCuAlx (x=0, 1, 2, 3) high-entropy alloy (HEA) coatings were prepared on Q345 steel by laser cladding. The effects of Al content on microstructure and properties of FeCrNiCoCuAlx HEA coatings were studied by XRD, SEM and erosion wear tests. The results show that the HEA coatings are mainly composed by simple FCC and BCC solid-solution phases. With the increase of Al addition, the microstructure is evolved gradually from FCC to BCC. And the hardness of the HEA coatings improves significantly and the maximum value is 580HV. In 3.5%NaCl solution, the corrosion current density of FeCrNiCoCuAlx HEA coatings decreases firstly and then increases with the increase of Al addition. And the HEA coating has the best corrosion resistance at x=1. Meanwhile, the mass loss rate of HEA coating decreases in the erosion test when the impact angle is changed from 90° to 30°, exhibiting an erosion characteristic of ductile materials. The slurry erosion properties of the HEA coating increase with the increase of Al content, and the erosion wear mechanism is evolved from forging extrusion to ploughing and micro-cutting.