In　a　novel　approach　that　capitalized　on　the　differential　solubility　product　(Ksp)　of　ZnSe　and　Ag2Se,　a　unique　ZnSe/Ag2Se　binary　heterostructure　was　efficiently　synthesized　in　situ.　ZnSe/Ag2Se　exhibited　excellent　antimicrobial　efficiency　under　visible　light.　Incorporating　Ag2Se　into　ZnSe　significantly　enhanced　the　photoelectric　performance　of　the　catalyst,　greatly　accelerating　the　separation　of　the　photogenerated　electrons　in　the　system.　Active　species　removal　experiments　determined　that　·O2-　and　H2O2　played　crucial　roles　in　photocatalytic　antibacterial　efficiency.　Further　investigation　into　the　levels　of　cellular　membrane　peroxidation,　bacterial　morphology,　and　intracellular　contents　concentration　revealed　that　during　the　photocatalytic　antimicrobial　process,　reactive　oxygen　species　initially　oxidize　phospholipids　in　the　cell　membrane,　leading　to　damage　to　the　external　structure　of　the　cell　and　leakage　of　the　intracellular　contents,　ultimately　resulting　in　bacteria　inactivation.　The　photocatalytic　antimicrobial　process　of　ZnSe/Ag2Se　fundamentally　deviates　from　conventional　methods,　offering　new　insights　into　efficient　disinfection　and　photocatalytic　antimicrobial　mechanisms.　©　2023　American　Chemical　Society