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The effects of (NH₄)₂ZrF₆ concentration, voltage and treating time on the corrosion resistance of ZK61M magnesium alloy micro-arc oxidation coatings were studied by orthogonal experiments. The SEM result shows that the surface roughness and porosity of MAO coatings increased with (NH₄)₂ZrF₆ concentration, voltage and treating time as a whole, except the porosity decreased with treating time. EDS, XRD and XPS analysis show that (NH₄)₂ZrF₆ was successfully incorporated into coatings by reactive incorporation, coatings are dominantly composed of ZrO₂, MgO, MgF₂ and amorphous phase Mg phosphate. Potentiodynamic polarization was used to evaluate the corrosion property of coatings. When the concentration of (NH₄)₂ZrF₆ is 6 g/L, the voltage is 450 V, and the treating time is 15 min, the coating exhibits the best corrosion resistance which corrosion current density is four magnitudes lower than substrate attributed to the incorporation of ZrO₂ and the deposition of MgF₂ in the micropores.