A　novel　magnetic　controlled　photoelectrochemical　(PEC)　sensing　system　was　designed　for　sensitive　detection　of　prostate-specific　antigen　(PSA)　using　reduced　graphene　oxide-functionalized　BiFeO3　(rGO-BiFeO3)　as　the　photoactive　material　and　target-triggered　hybridization　chain　reaction　(HCR)　for　signal　amplification.　Remarkably　enhanced　PEC　performance　could　be　obtained　by　using　rGO-BiFeO3　as　the　photoelectrode　material　due　to　its　accelerated　charge　transfer　and　improved　the　visible　light　absorption.　Additionally,　efficient　and　simple　operation　could　be　achieved　by　introducing　magnetic　controlled　flow-through　device.　The　assay　mainly　involved　in　anchor　DNA-conjugated　magnetic　bead　(MB-aDNA),　PSA　aptamer/trigger　DNA　(Apt-tDNA)　and　two　glucose　oxidase-labeled　hairpins　(H1-GOx　and　H2-GOx).　Upon　addition　of　target　PSA,　the　analyte　initially　reacted　with　the　aptamer　to　release　the　trigger　DNA,　which　partially　hybridized　with　the　anchor　DNA　on　the　MB.　Thereafter,　the　unpaired　trigger　DNA　on　the　MB　opened　the　hairpin　DNA　structures　in　sequence　and　propagated　a　chain　reaction　of　hybridization　events　between　two　alternating　hairpins　to　form　a　long　nicked　double-helix　with　numerous　GOx　enzymes　on　it.　Subsequently,　the　enzymatic　product　(H2O2)　generated　and　consumed　the　photo-excited　electrons　from　rGO-BiFeO3　under　visible　light　irradiation　to　enhance　the　photocurrent.　Under　optimal　conditions,　the　magnetic　controlled　PEC　sensing　system　exhibited　good　photocurrent　responses　toward　target　PSA　within　the　linear　range　of　0.001　−　100　ng/mL　with　a　detection　limit　of　0.31　pg/mL.　Moreover,　favorable　selectivity,　good　stability　and　satisfactory　accuracy　were　obtained.　The　excellent　analytical　performance　suggested　that　the　rGO-BiFeO3-based　PEC　sensing　platform　could　be　a　promising　tool　for　sensitive,　efficient　and　low　cost　detection　of　PSA　in　disease　diagnostics.　©　2017　Elsevier　B.V.