Abstract: CoCrFeNi high-entropy alloy coatings were prepared on the surface of 304 stainless steel by laser cladding technology, and subsequently annealed at 500℃ for 2 hours. The microstructure, hardness and residual stress of the coatings and their effects on cavitation resistance were studied, and forming mechanism and cavitation damage behavior of high-entropy alloy coatings were revealed. Results indicated that the high-entropy alloy coating is a face-centered cubic (FCC) single-phase solid solution structure, and the overall quality of the coating is excellent, with no obvious pores and cracks. The top region is mainly equiaxed cellular crystals and the bottom is columnar dendritic crystals, and the average microhardness is 247.1 HV0.3, which is about 1.4 times that of 304 stainless steel. The coating has good thermal stability, after annealing, the physical phase of the coating did not change, and the dendritic crystal microstructures underwent a slight growth, resulting in a slight softening of the coating, but the tensile residual stress on the coating surface was released, and the σ_x and σ_y were reduced by 67% and 76%, respectively. Cavitation cumulative mass loss of 304 stainless steel and coating with and without annealing is about 13.86 mg, 6.38 mg and 5.94 mg, respectively. The cavitation resistance of the coating was significantly higher than that of stainless steel, with a cavitation rate of 44% to that of the substrate. The CoCrFeNi high-entropy alloy coating can significantly improve the cavitation resistance of 304 stainless steel, and the cavitation resistance is further improved after the coating is annealed because the tensile residual stress is released after annealing, resulting in the suppression of cavitation fatigue crack extension.