A　facile　approach　is　developed　to　synthesis　the　highly　efficient　photocatalyst　of　Bi2O2CO3/BiOCl.　The　composite　of　Bi2O2CO3/BiOCl　exhibits　excellent　photocatalytic　activity　toward　Rhodamine　B　(RhB)　under　visible　light,　which　is　even　better　than　that　of　P25　(commercial　TiO2)　under　UV　light.　The　role　of　the　active　species　in　the　process　of　the　degradation　is　evaluated　by　using　different　types　of　active　species　scavengers　and　measurement　of　electron　spin　resonance　(ESR).　The　relative　band　structures　of　the　Bi2O2CO3　and　BiOCl　are　determined　combined　with　the　flat　potential　(Vfb)　and　bandgap　energy　(Eg)　evaluated　by　UV-vis　diffuse　reflectance　spectra.　The　results　show　that　the　composite　of　the　two　semiconductors　facilitates　the　photosensitized　degradation　of　RhB　under　visible　light　(420nm<λ<800nm).　And　the　essence　of　RhB　photosensitization　is　revealed　to　be　the　increase　of　H2O2　in　the　reaction　system.　The　photocatalytic　mechanism　is　further　proposed,　which　unfolds　the　charge　transfer　and　the　active　species　formed　in　the　photcatalytic　process.　The　work　may　set　foundation　for　application　of　the　new　photocatalyst　of　Bi2O2CO3-based　heterostructure.　©　2016　Elsevier　B.V.