Recycled Mg-alloys with high Al content (~2.3%) exhibit undesirable corrosion resistance due to their high second phase impurities, thus proper surface treatment is required for practical applications. In this work, a novel micro-arc oxidation (MAO) process was applied to a high-Al recycled Mg-alloy, while without introducing any extra particles into the electrolyte, a layered double hydroxide (LDH) film was formed, enabling the one-step fabrication of a MAO/LDH composite film. The surface and cross-sectional morphologies of the alloys with MAO/LDH film were analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), and their corrosion performance was also assessed by electrochemical tests and hydrogen evolution measurement. It is revealed that the MAO/LDH composite layer exhibits a dual-layer structure with uniform elemental distribution. The inner MAO layer with a thickness of ~2.72 μm mainly consists of MgO whereas the outer layer, confirmed as Mg-Al LDH via TEM analysis, shows a thickness of ~60 nm, which is rich in Mg, O, P, and Al. Compared to the bare Mg-alloy, the MAO/LDH-coated Mg-alloy demonstrated significantly enhanced corrosion resistance: the hydrogen evolution rate was reduced by 28-fold, and the free-corrosion current density decreased by three orders of magnitude. This study provides a feasible strategy for one-step fabrication of MAO/LDH composite coatings on Mg-alloys, offering insights into improving the corrosion resistance of recycled Mg-alloys with high impurity content.