This paper is to study the effect of Al content on the microstructure and tribology performance of high-entropy composite coating reinforced by endogenous alumina particles. In the process of laser cladding, metal oxides were reduced and deposited on the surface of Q235 steel by thermite reaction to prepare AlxCoCrFeNi (x=0, 0.3, 1, 1.5, 2) high-entropy composite coating reinforced by endogenous Al2O3 ceramic particles. XRD, SEM, EDS, XPS, RAMAN, friction test and other experimental methods were used to study the microstructure and tribology performance of the high-entropy composite coatings. The results show that there are dispersed nano-sized Al2O3 ceramic particles in the coating. With the increase of Al content, the microstructure of the high-entropy composite coating gradually changes from FCC and BCC coexistence to BCC single phase. At the same time, the friction coefficient and wear rate of the high-entropy composite coating under 10 N load decreased with the increase of Al content. Al2CoCrFeNi has the lowest friction coefficient (0.15) and the lowest wear rate (1.01×10–6 mm3/(N.m)), which are 1/4 and 1/38 of the base Q235 steel respectively. When x in AlxCoCrFeNi coating increases to 2, the peeling phenomenon of the wear scar surface disappears. The main wear form of the coating changes from oxidative wear and fatigue wear to slight abrasive wear. The average friction coefficient of Al2CoCrFeNi coating increased to 0.325 under a load of 20 N. Increasing the Al element in the composite coating can stabilize the BCC phase and refine the structure. At the same time, excessive Al element can inhibit Fe element oxidation and increase the content of Fe3O4 on the surface of the wear scar, thereby significantly reducing the friction coefficient of the composite coating and improving its friction reduction and wear resistance.