<p>The mathematical model between laser cladding parameters and coating properties was established by the response surface method (RSM). Ni–WC-reinforced CoCrNiFeAl high-entropy alloy (HEA) composite coatings were prepared on the surface of 0Cr13Ni5Mo steel by laser cladding to study the addition of Ni–WC on slurry erosion resistance of coatings. The optimal parameters obtained by RSM are laser power of 1450 W, scanning speed of 4.3&#xa0;mm/s, powder feeding speed of 1.3 r/min and overlap rate of 60%, respectively. The grains of CoCrNiFeAl composite coatings are refined by adding Ni–WC-reinforced powder. 15 wt.% Ni–WC composite coating presents the maximum microhardness with the value of 655 HV_0.3. The cumulative mass loss of the composite coatings at different erosion angles is lower than that of the pure CoCrNiFeAl coating. In addition, at low erosion angles, the cumulative mass loss of the composite coatings gradually decreases with the increase in the mass fraction of Ni–WC. Ploughing and microcutting are the primary erosion mechanisms of CoCrNiFeAl composite coatings at low erosion angles. When erosion damage occurs at high erosion angle, the erosion mechanisms of composite coating material loss are dominated by lip formation and craters. The proposed high-entropy alloy composite coatings can be applied to improve the erosion resistance of components in contact with high-speed fluids, such as ship propellers and centrifugal pump blades.</p>