The　efficiency　of　hydrogen　peroxide　evolution　reaction　(H2O2ER)　by　photoanodic　water　oxidation　is　normally　limited　by　low　yield　and　poor　selectivity.　In　this　work,　the　surfaces　of　Mo　doped　BiVO4　are　modified　by　Co2+　and　PO43-　ions　(CPMB),　which　has　been　used　as　the　photoanode　with　improved　H2O2　yield　and　selectivity.　The　optimal　evolution　rate　of　the　CPMB　is　ca.　0.23　mmol.min(-1).cm(-2),　corresponding　to　2.5　times　to　the　pristine　BiVO4　photoanode,　and　the　faradaic　efficiency　of　CPMB　photoanode　for　H2O2ER　is　ca.　26%.　In　this　study,　the　mechanism　for　the　improved　H2O2　evolution　performance　of　CPMB　has　been　investigated,　indicating　that　PO43-　ions　mainly　promote　the　formation　of　the　.OH　by　dissociation　of　H2O,　while　Co2+　ions　accelerate　the　conversion　of　the　.OH　for　the　subsequent　H2O2　evolution.　This　study　offers　the　strategy　for　designing　an　efficient　photoelectrochemical　system　with　optimized　solar　conversion　efficiency　for　H2O2　production.