To　enhance　the　separation　efficiency　of　photo-generated　carriers,　a　p–n　junction　photocatalyst　BiOI/NaNbO　3　has　been　fabricated　by　a　facile　method.　The　obtained　samples　were　characterized　by　XRD,　SEM,　TEM,　HRTEM,　PL,　N　2　sorption–desorption　and　DRS.　DRS　results　showed　that　the　light　absorption　edges　of　BiOI/NaNbO　3　hybrids　were　red-shifted　with　the　increase　of　BiOI　content.　The　SEM　and　TEM　images　revealed　that　the　BiOI　was　widely　decorated　over　the　surfaces　of　NaNbO　3　cubes.　The　formation　of　p–n　heterojunction　at　their　interfaces　was　proved　by　the　HRTEM　image.　The　visible　light-driven　photocatalytic　activity　was　evaluated　by　the　degradation　of　methylene　blue　(MB)　in　aqueous　solution.　Compared　with　single　NaNbO　3　and　BiOI,　the　BiOI/NaNbO　3　hybrid　photocatalysts　have　exhibited　significantly　enhanced　activities.　Meanwhile,　the　mass　ratio　of　BiOI/NaNbO　3　displayed　important　influence　on　the　MB　degradation.　The　hybrid　photocatalyst　with　BiOI　content　of　40%　performed　the　optimal　activity.　This　activity　enhancement　should　be　attributed　to　the　strong　visible　light　absorption,　the　high　migration　and　separation　efficiency　of　photo-induced　carriers.　The　photocurrent　and　PL　measurements　confirmed　that　the　interfacial　charge　separation　efficiency　was　greatly　improved　by　coupling　BiOI　with　NaNbO　3　.　Controlled　experiments　proved　that　the　degradation　of　pollutants　was　mainly　attributed　to　the　oxidizing　ability　of　the　generated　holes　(h　+　),　·O　2　−　,　and　·OH　radicals.　©　2017