Ceramic coatings were formed by micro-arc oxidation in a phosphate electrolyte solution on aluminium alloy with and without a high temperature oxidation prefab film respectively. The effect of prefab films on the micro-arc oxidation coatings was studied. The results show that the high temperature oxidation prefab film is conducive to decrease of the arc starting voltage of the micro-arc oxidation and increase rate of the growth of micro-arc oxidation coatings; The growth process of the micro-arc oxidation ceramic coatings contains the formation of grain type of melted lumps, the expansion of the lumps in line along the sample surface, the formation of many network areas with a number of linear materials and the development of network areas into a continuous layer. In the process of MAO, the growth of ceramic coating mainly relies on the melting of high temperature oxidation film in the initial stage, and the melting of aluminium alloy matrix in the later stage. Compared with the later stage, the high temperature oxidation film makes greater effect on the initial stage, but the ceramic coating formed in the initial stage plays an important role on the growth of ceramic coating in the later stage.