Applying the technology of micro plasma oxide to form ceramic layer in situ on aluminum alloy7075.The optimum electrolyte recipe of micro plasma oxidation on aluminum alloy 7075 in borate system was optimized by orthogonal experiment, the morphology and the phase composition of the ceramic layer were analyzed by SEM and XRD.Results show that the hardness of ceramic layer reaches 812HV0.1; The surface morphology of ceramic layer is homogenous, ceramic layer is composed of γ-Al2O3 primarily and it is very compact.