Abstract: The electrolyte and the colorant for preparation of black micro-arc oxidation ceramic layer of aluminum alloy were introduced in detail firstly. Secondly, the influence mechanism of different electrolytic liquid systems on the microstructure, composition, growth mode and mechanical properties of the black micro-arc oxidation ceramic layer of aluminum alloy was analyzed. The formation process and growth mechanism of the black ceramic layer were expounded.Finally, the coloring mechanism of the black micro-arc oxidation ceramic layer was discussed through the chemical state of the colorant elements.