Efficient　separation　of　photo-induced　electrons　and　holes　in　the　photoelectrochemical　(PEC)　sensors　plays　an　important　role　in　improving　detection　sensitivity.　Based　on　this　point,　we　report　a　simple　and　sensitive　photoelectrochemical　bioassay　for　prostate-specific　antigen　(PSA)　detection　using　lanthanide-doped　bismuth　ferrite/reduced　graphene　oxide/tungsten　oxide　nanohybrids　(BLFO/rGO/WO3)　as　the　photo-sensing　material.　Initially,　WO3　was　excited　under　the　continuous　illumination　to　generate　photo-induced　electron-hole　pairs.　Then,　rGO　(as　a　suitable　charge　transfer　medium)　could　effectively　build　a　bridge　between　WO3　and　BLFO.　With　the　mediation　of　the　built-in　electric　field　in　BLFO,　the　transferred　charges　were　allowed　for　directional　migration　in　the　circuit,　thus　achieving　an　effective　separation　of　the　photogenerated　electron-hole　pairs.　Coupling　with　the　amplification　of　enzymatic　production　(H2O2)　and　specific　recognition　of　antigen-antibody　immunoreaction,　target　concentration　was　relative　to　the　corresponding　photocurrent,　thereby　realizing　the　PSA　sensitive　detection.　Under　optimal　conditions,　the　PEC　immunoassay　exhibited　a　good　linear　relationship　within　a　dynamic　working　range　from　0.1　ng　mL-1　to　200　ng　mL-1　with　a　detection　limit　of　49.4　pg　mL-1.　In　addition,　this　study　afforded　satisfying　specificity,　reproducibility,　and　long-term　storage,　which　also　matched　well　with　the　commercial　PSA　ELISA　kit.　This　journal　is　©　The　Royal　Society　of　Chemistry.