Cyanobacterial　harmful　algal　blooms　(CyanoHABs)　and　the　release　of　cyanotoxins　have　posed　adverse　impacts　to　aquatic　system　and　human　health.　In　this　study,　a　novel　self-floating　Ag/AgCl@LaFeO3　(ALFO)　photocatalytic　hydrogel　was　prepared　via　freeze-thaw　method　for　removal　of　Microcystis　aeruginosa　(M.　aeruginosa).　The　ALFO　hydrogel　performed　an　excellent　photocatalytic　activity　with　a　99.4%　removal　efficiency　of　chlorophyll　a　within　4　h.　It　can　still　remove　above　95%　chlorophyll　a　after　six　consecutive　recycles.　Besides　it　has　also　shown　excellent　mechanical　strength　and　elasticity,　which　can　ensure　its　use　in　practical　applications.　The　mechanisms　of　M.　aeruginosa　inactivation　are　attributed　to　•O2−　and　•OH　generated　by　the　ALFO　hydrogel　under　visible　light　radiation.　In　addition,　•O2−　and　•OH　can　further　oxidative　degrade　and　even　mineralize　the　leaked　algae　organic　matter,　avoiding　the　recurrence　of　CyanoHABs.　What＇s　more,　the　ALFO　hydrogel　owns　good　photocatalytic　degradation　performance　for　microcystins-LR　(MC-LR)　with　a　97%　removal　efficiency　within　90　min.　A　possible　photocatalytic　degradation　pathway　of　MC-LR　was　proposed　through　the　identification　of　the　intermediate　products　during　the　photocatalytic　reaction,　which　confirmed　the　reduction　of　MC-LR　toxicity.　This　work　develops　recyclable　a　self-floating　ALFO　hydrogel　to　simultaneously　inactivate　M.　aeruginosa　and　degrade　MC-LR,　providing　a　prospective　method　for　governing　and　controlling　CyanoHABs　in　practical　application.　©　2021　Elsevier　Ltd