Abstract　The　systematic　clarification　of　the　photocatalytic　process　is　an　indispensable　basis　for　the　in-depth　understanding　of　the　photocatalytic　mechanism.　Various　types　of　active　oxygen　species　involved　into　the　photocatalytic　process　have　been　investigated　extensively,　including　OH　and　O2-,　but　still　remain　obscure　and　controversial.　Herein,　the　roles　of　the　active　oxygen　species　generated　in　the　liquid-phase　photocatalytic　degradation　of　RhB　using　BiVO4/TiO2　heterostructure　under　visible　light　irradiation　are　discussed　in　detail.　The　results　revealed　that　the　liquid-phase　photocatalytic　degradation　behavior　was　greatly　affected　by　the　amount　of　BiVO4.　When　the　loading　BiVO4　was　less　than　9　wt%,　the　de-ethylation　of　RhB　on　BiVO4/TiO2　was　observed.　While,　the　direct　oxidative　degradation　of　RhB　took　place　in　the　BiVO4/TiO2/RhB　system　loaded　with　more　BiVO4　(＞9　wt%).　Particularly,　9%　BiVO4/TiO2　enhanced　the　photosensitized　degradation　of　RhB,　and　the　degradation　efficiency　was　80%　which　was　1.14　times　than　that　of　pure　TiO2.　Combined　with　different　surface　analysis　techniques　(EPR,　photoluminescence　technique,　etc.),　it　was　found　that　O2-　and　OH　were　the　key　active　species　when　the　loading　BiVO4　was　less　than　9　wt%,　while　in　the　50%　BiVO4/TiO2/RhB　system,　O2-　and　holes　played　much　more　roles.　Our　findings　provide　certain　theoretical　guidance　in　understanding　the　functional　mechanism　of　heterostructured　photocatalysts,　which　can　pave　the　way　to　further　improve　the　concentration　of　the　active　species　and　design　novel　efficient　photocatalysts.　©　2015　Elsevier　B.V.