The　grain　size　and　surface　oxygen　vacancy　concentration　of　ZnO　have　great　influence　on　its　photocatalytic　performance.　In　this　work,　caged　Iodine-modified　ZnO　(I-ZnO-n)　catalyst　with　nano-structure　and　surface　oxygen　vacancy　were　successfully　prepared　by　reflux　method.　The　crystal　structure,　surface　properties　and　optical　properties　were　characterized　by　XRD,　SEM,　TEM,　RAMAN,　ESR　and　EPR.　And　the　photocatalytic　antibacterial　activity　under　visible　light　has　been　tested.　The　results　show　that　the　nano-structure　I-ZnO-n＇s　band　gap　is　narrow　than　ZnO　because　of　the　existence　of　oxygen　vacancy.　And　I-ZnO-n　exhibits　better　antibacterial　property　than　micron-structured　Iodine-modified　ZnO.　The　ESR　and　electrochemical　experiments　confirm　that　the　I-ZnO-n　has　much　more　surface　oxygen　vacancy　and　higher　separation　efficiency　of　photogenic　carriers　than　micron-structured　Iodine-modified　ZnO,　which　results　its　superior　photocatalytic　performance.