This paper aims to optimize the surface mechanical properties of Q235 steel by cladding the AlCoCrFeNiCu high-entropy alloy coating by pulsed Nd:YAG solid-state laser. Orthogonal experiment method is proposed to optimize laser cladding process parameters, and the X-ray diffractometer, scanning electron Microscope (SEM), energy spectrometer (EDS), Microhardness tester were carried out to analyze the phase composition, microstructure, element composition and hardness distribution of the coating. A three-electrode system was used to test the polarization performance and electrochemical impedance spectroscopy (EIS) of the high-entropy alloy coating to study its corrosion resistance in 3.5wt.%NaCl solution. The results taking dilution rate and hardness as response to analyze its range and variance, and the optimal process parameters were obtained as coating thickness of 1.25 mm, scanning speed of 180 mm/min, current size of 220 A, and defocus amount of ?7 mm. The Cu-rich FCC phase and the (Al, Ni) BCC phase constitute the high-entropy alloy coating phase. The Cu element segregates between the dendrites. The microstructure of the surface layer is fine and uniform equiaxed crystals, the middle part is thick columnar dendrites, and the plane crystals can be observed at the junction between the bottom of the coating and the substrate obviously. Furthermore, the maximum hardness of the coating reaches 521HV0.2, which is 2.7 times that of the substrate. In 3.5wt.%NaCl solution, the high entropy alloy coating of AlcoCrFeNiCu shows good corrosion resistance than the substrate with a more positive self-corrosion potential, smaller self-corrosion current density, larger reactance arc radius and impedance film value. In conclusion, the laser cladding technology can produce high-entropy alloy coatings with good forming and performance, and the AlCoCrFeNiCu high-entropy alloy coating can protect the substrate by effectively improve the corrosion resistance.