Flexible　high-sensitivity　photodetectors　are　desirable　for　use　in　future　wearable　optoelectronics.　Graphene　is　attracting　considerable　attention　because　of　its　outstanding　electrical,　optical,　and　mechanical　properties,　which　make　graphene　appealing　in　flexible　optoelectronics　and　photodetection　applications.　In　this　paper,　an　internal　current　gain　mechanism　is　proposed　based　on　a　2D/0D　photodetection　system.　The　carrier　density　in　the　2D　material　can　be　amplified　via　Fermi　level　modulation　when　a　0D　quantum　dot　absorbs　photons.　An　ultrahigh　responsivity　of　more　than　10(10)　A　W-1　and　fW-scale　light　detectivity　are　achieved　at　room　temperature　using　the　flexible　transfer-free　hybrid　graphene/Cu2O　quantum　dot　photodetector　developed　in　this　work.　After　excessive　bending,　the　responsivity　of　the　photodetector　still　reaches　10(6)　A　W-1,　thus　demonstrating　the　promising　flexibility　of　the　device.