In this study, ceramic particle (WC) reinforced AlCoCrFeNi2.1 eutectic high entropy matrix composites (WCx/HEA1-x, x = 0, 5, 10wt%) were prepared by using laser powder bed fusion (LPBF) technology. The microstructure evolution and wear behavior of the printed WCx/HEA1-x composites were analyzed, and the strengthening mechanism and anti-wear mechanism of the WCx/HEA1-x composites were extensively studied. The results show that the reinforcement ceramic particles (WC) were uniformly distributed in the HEA matrix and a good metallurgical bonding layer between the reinforced phase WC and the HEA matrix were found. The maximum width of the bonding layer is about 330 nm. Under the strong irradiation of high-energy laser, WC was decomposed into W and C elements, and diffused into the HEA matrix. Its reaction with Co, Fe, Ni elements produced MxC (M = Co, Fe, Ni) carbides. Part of W and C elements were soluble in the HEA. The wear resistance of the printed composite is found affected by the content of added ceramic particle (WC). The ranking of the wear resistance of the printed composites was found to be WC0.05/HEA0.95 > HEA ≈ WC0.10/HEA0.90. The improvement of wear resistance by adding WC was found due to interfacial load transfer strengthening of WC particles, solution strengthening of W and C atoms; and the second phase strengthening of various carbides MxC (M = Co, Fe, Ni).