In　recent　years,　photocatalytic　technology　has　been　increasingly　used　for　the　treatment　of　algal　blooms　in　water　bodies　due　to　its　high　efficiency　and　environmental　advantages.　However,　conventional　semiconductor　materials　suffer　from　high　electron-hole　recombination　rate,　low　carrier　mobility　and　weak　surface　adsorption　ability,　which　made　their　photocatalytic　performance　limited.　Therefore,　the　photocatalytic　performance　of　the　composites　can　be　improved　by　coupling　another　semiconductor　material　to　form　a　heterojunction　to　accelerate　electron　transfer.　In　this　study,　a　novel　composite　Ag3VO4/BiVO4　(ABV)　photocatalyst　was　successfully　prepared　by　in-situ　deposition　method　for　the　photocatalytic　inactivation　of　Microcystis　aeruginosa　(M.　aeruginosa)　under　visible　light.　The　photocatalyst　showed　excellent　photocatalytic　activity,　and　the　degradation　rate　of　M.　aeruginosa　chlorophyll　a　was　up　to　99.8%　within　4　h　under　visible　light.　During　the　photocatalytic　degradation,　the　morphology　of　algae　cells,　the　permeability　of　cell　membrane,　the　organic　matter　inside　and　outside　the　cells,　the　antioxidant　system　and　the　soluble　protein　were　seriously　damaged.　Moreover,　three　cycle　experiments　showed　that　the　prepared　ABV　photocatalyst　had　high　reusability.　Finally,　a　possible　mechanism　of　M.　aeruginosa　inactivation　was　proposed.　In　general,　the　synthesized　ABV　photocatalyst　can　effectively　inactivate　cyanobacteria　under　visible　light　and　provided　a　new　method　for　M.　aeruginosa　removal　in　water.　©　2023　Elsevier　Ltd