The design and preparation of antifriction coating on the surface of aluminum alloy is one of the key technologies to improve the friction properties of aluminum alloy components. In this study, nano-MoS2 was synthesized in situ on the surface of 6063 aluminum alloy by one-step micro-arc oxidation method to prepare MoS2/Al2O3 composite ceramic coating with antifriction effect. The effect of sulfur concentration on the composition, morphology and friction properties of the coating was discussed. The friction reducing mechanism of the coating was analyzed. The results show that the self-lubricating composite ceramic coating containing MoS2 was successfully prepared on the surface of 6063 aluminum alloy by micro-arc oxidation. The friction coefficient of the coating decreases first and then increases with the increase of the sulfur concentration. When the sulfur concentration in the electrolyte is 15g/L, the friction coefficient of the coating is 0.15, which is reduced by 76% compared with the conventional micro-arc oxidation coating. The MoS2 in the coating is distributed on the surface and inside of the coating. Under the action of contact and extrusion with the friction pair, a uniformly distributed MoS2 lubricating film is formed, showing good antifriction performance.