The　utilization　of　photoelectrochemical　cathodic　protection　(PECCP)　enables　an　indirect　corrosion　protection　of　metals　with　low　self-corrosion　potential　by　introducing　a　metallic　nickel　interlayer.　However,　the　ability　to　enhance　the　PECCP　efficiency　remains　challenging　because　of　the　inherent　property　of　the　semiconductor.　Herein,　this　ability　is　demonstrated　by　coupling　a　covalent　organic　framework　(TpBD)　decorated　TiO2　photoanode　(TiO2/TpBD)　with　nickel　coating　on　magnesium　alloy　for　an　effective　corrosion　protection.　The　composite　photoanode　showed　direct　PECCP　for　the　nickel　interlayer　and　indirect　corrosion　protection　of　the　magnesium　alloy.　The　composite　structure　of　the　nanotube　array　and　the　covalent　organic　framework　for　the　photoanode　were　confirmed　by　field　emission　scanning　electron　microscopy　(FESEM),　transmission　electron　microscopy　(TEM),　and　X-ray　photoelectron　spectroscopy　(XPS).　The　enhanced　photoelectrochemical　conversion　capability　and　PECCP　performance　of　the　nickel-coated　Mg　alloy　were　evidenced　by　the　results　from　electrochemical　and　photoelectrochemical　measurements　including　Mott-Schottky　curves,　photoinduced　potential　variations,　and　electrochemical　impedance　spectroscopy　(EIS).　Lastly,　a　corrosion　protection　mechanism　is　proposed,　where　the　enhanced　PECCP　efficiency　is　attributed　to　the　formation　of　a　direct　Z-scheme　heterojunction,　which　is　substantiated　by　the　results　from　valence　band　(VB)　XPS　and　electron　spin　resonance　characterizations.　©　2022