Three　kinds　of　GO-based　Z-scheme　photocatalytic　materials　were　synthesized　to　remove　harmful　algae　and　Microcystins-LR　(MC-LR).　The　physicochemical　properties　of　the　photocatalysts　were　characterized.　The　inhibitory　effects　of　three　photocatalysts　on　the　growth　of　algae　under　visible　light　were　compared.　The　photocatalytic　degradation　pathways　and　mechanism　of　MC-LR　by　Ag2CO3-GO　were　proposed.　The　results　showed　that　the　combination　modes　and　morphology　size　of　GO-based　Z-scheme　photocatalysts　had　grade　effects　on　the　degradation　of　MC-LR.　Ag2CO3-GO　exhibited　the　best　photocatalytic　activity　among　these　GO-based　Z-scheme　photocatalysts,　which　could　remove　nearly　100%　MC-LR　(0.3　mg/L)　within　1　h　under　visible　light.　The　degradation　rate　of　MC-LR　by　Ag2CO3-GO　fit　well　with　the　pseudo-first-order　kinetic　model　and　was　significantly　influenced　by　pH.　The　degradation　of　MC-LR　by　Ag2CO3-GO　was　also　inhibited　by　the　alkalinity,　DOM,　H2O2,　and　the　coexistence　of　algae　cells.　The　experimental　results　showed　that　OH　and　O-2　played　the　main　role　in　the　photocatalysis　of　MC-LR　by　Ag2CO3-GO,　and　the　Adda　side　chain　and　peptide　ring　in　MC-LR　were　gradually　oxidized,　indicating　that　the　biological　toxicity　of　MC-LR　was　gradually　lost　during　the　degradation　process.　Besides,　100　mg/L　of　Ag2CO3-GO　could　obviously　inhibit　the　growth　of　harmful　algae,　which　could　oxidize　and　damage　algae　cells,　and　further　degrade　their　released　contents　under　visible　light,　thus　avoiding　the　secondary　pollution　effectively.　In　summary,　GO-based　Z-scheme　photocatalysts　have　a　promising　future　for　the　inactivation　of　harmful　cyanobacteria　and　degradation　of　MC-LR.