As　an　effective　means　to　promote　photoinduced　carrier　separation,　the　construction　of　Z-scheme　heterojunction　photocatalysts　can　be　widely　used　for　the　degradation　of　organic　pollutants.　In　this　work,　an　innovative　peanut　shell　biochar/Ag3PO4/AgI　ternary　composite　was　prepared,　and　the　chemical　compositions,　structural　morphology,　optical　and　photoelectrochemical　properties　of　the　photocatalyst　were　characterized.　The　peanut　shell　biochar/Ag3PO4/AgI　composite　delivered　a　high　photodegradation　efficiency　of　MB　at　99.7　%　in　60　min　with　kinetic　constant　of　0.0366　min−1,　which　is　about　3.81,　9.89,　and　1.17　times　that　Ag3PO4　(0.0096　min−1),　AgI　(0.0037　min−1)　and　Ag3PO4/AgI　(0.0313　min−1),　respectively.　Meanwhile,　the　composite　also　exhibits　excellent　photocatalytic　activity　for　methyl　orange,　rhodamine　B,　congo　red,　tetracycline　and　ofloxacin.　Based　on　radical　capture　experiments　and　photoelectrochemical　test,　the　possible　photocatalytic　mechanism　was　revealed.　Compared　with　monomers,　biochar/Ag3PO4/AgI　exhibits　higher　photocatalytic　degradation　activity　under　visible　light　irradiation,　which　was　due　to　the　introduction　of　electron-transporting　biochar　into　the　composite,　and　the　formation　of　heterostructure　between　Ag3PO4　and　AgI,　which　enhance　the　separation　rate　of　photoinduced　carriers.　The　excellent　stability　and　photocatalytic　activity　make　peanut　shell　biochar/Ag3PO4/AgI　an　ideal　photocatalyst　to　solve　environmental　crisis.　©　2024　Wiley-VCH　GmbH.