A　biodegradable　hydroxyapatite/graphene　oxide　bio-composite　(HA/GO)　coating　has　been　fabricated　on　magnesium　(Mg)　alloy　by　a　convenient　one-step　method　of　micro-arc　oxidation　(MAO)　for　biodegradable　implants.　The　microstructure　and　phase　constituents　of　the　obtained　powders　and　coatings　were　characterized　by　XRD,　SEM,　TEM,　FT-IR,　XPS　and　the　corrosion　resistance　in　vitro　has　been　investigated　by　electrochemical　measurements　in　simulated　body　fluid　(SBF).　The　results　suggested　that　HA/GO　powder　has　been　successfully　prepared　and　filled　into　the　discharging　pores　of　the　coating　during　MAO　process.　The　electrochemical　measurements　in　SBF　indicated　that　the　corrosion　current　of　Mg　substrate　has　been　significantly　decreased　by　the　HA/GO　coating.　Furthermore　the　EIS　measurement　suggested　that　the　HA/GO　coating　more　effectively　inhibited　the　Mg　substrate　from　corrosion　compared　to　pure　MAO　coating.　These　results　suggested　that　HA/GO　coating　on　Mg　alloy　could　be　a　promising　candidate　for　biomedical　application.　©　2017　Elsevier　B.V.