Abstract: Ni60B nickel based alloy coatings and micro WC, nano WC and micro-nano WC particle reinforced Ni60B composite coatings were fabricated using laser cladding technology, hereinafter called as WCm, WCn and WCmn coatings,respectively. Sliding wear tests at different loads and sliding distances were conducted for the coatings using an Amsler200 tester under water lubrication conditions. The results show that the addition of WC particles can improve the wear resistance of Ni60B coatings and that the wear resistance of the WCm and WCn coatings does not presentan obvious difference, however their worn morphologiesare different. The wear resistance of the coatings is much better under water lubrication than dry sliding wear because the water lubrication film can play a support or isolating action between the coatings and the wear wheel, which decreases their contact stress, and because water cooling to friction couples decreases the temperature rising and the softening of the coatings. W element which is saturated in the WCn and WCm-coatings diffuses and agglomeratesduring water lubrication wear.