Diamond reinforced Al0.5CoCrFeNiTi0.5 high-entropy alloy (HEA) coatings were prepared on 30CrMnSi substrate by laser cladding in this work. The abrasive wear behavior and mechanism of the prepared coatings were evaluated by a dry sand rubber wheel test. The results show that the hardness of the HEA coatings can be greatly improved by adding diamond particles. The hardness of the HEA coating with 15 vol.% diamond reaches 706 HV1.0, which is 3 times that of the substrate and 35% higher than the coating without diamond addition. The abrasive wear resistance of the diamond reinforced HEA coatings is much higher than that of the substrate and the HEA coatings without diamond addition. The wear rate of the HEA coating with 15 vol.% diamond addition is only about 1/14 of that of the 30CrMnSi substrate and 1/13 of that of the HEA coatings without diamond addition. The main abrasive wear mechanisms of the samples are micro-cutting and surface plastic deformation. For the substrate and HEA coatings without diamond, micro-cutting dominates due to the low hardness, forming narrow and deep grooves on the samples surface. While for the diamond reinforced HEA coatings, surface plastic deformation dominates. At the same time, the diamond particles in the coatings hinder the plastic deformation and micro-cutting during the abrasive wear process, resulting in the further increase of the wear resistance of the diamond reinforced HEA coatings.