The　frequent　harmful　algae　blooms　(HABs)　in　eutrophic　waters　pose　serious　threats　to　the　water　environment　and　health　of　human　beings　and　animals.　In　this　study,　a　new　type　of　photocatalytic　coating　was　prepared　by　loading　Ag2CO3-N:GO　(AGON)　on　the　polyurethane　sponge　modified　by　silica　sol　via　a　dip　coating　method　for　the　photocatalytic　inactivation　of　Microcystis　aeruginosa　(M.　aeruginosa)　and　degradation　of　Microcystin-LR　(MC-LR).　The　factors　including　photocatalyst　loading　dosage,　natural　organic　matter　(NOM),　and　alkalinity　were　studied.　The　effects　on　the　physiological　characteristics　of　M.　aeruginosa　and　reactive　oxygen　species　(ROS)　were　also　investigated　to　reveal　the　photocatalytic　inactivation　mechanisms.　The　results　showed　that　the　AGON　coating-4　(the　initial　concentration　of　AGON　suspension　used　for　loading　is　4　g/L)　exhibited　the　optimum　photocatalytic　performance　under　visible　light,　which　can　completely　remove　chlorophyll　a　after　5　h　of　irradiation.　And　the　NOM　and　alkalinity　in　water　have　relatively　negative　effects　on　the　photocatalytic　inactivation　of　algae.　The　prepared　AGON　coating　also　exhibited　excellent　photocatalytic　performance　in　the　degradation　of　MC-LR　under　visible　light.　It　only　needed　20,　60　and　120　min　to　completely　degrade　0.1,　0.3　and　0.5　mg/L　MC-LR,　respectively.　However,　the　mixed　systems　of　algae　and　MC-LR　required　a　longer　time　to　achieve　photocatalytic　degradation.　The　[rad]O2−　were　the　predominant　reactive　oxygen　species,　causing　the　damage　of　cell　membranes　and　walls　and　the　leakage　of　cellular　content,　which　eventually　led　to　the　irreversible　damage　to　algal　cells.　What＇s　more,　the　coating　can　be　reused　several　times　due　to　its　good　cyclability　and　stability.　Therefore,　the　AGON　coating　has　promising　prospects　for　the　treatment　of　algal　blooms　in　eutrophic　waters.　©　2020