In　this　work,　a　new　＂signal-on＂　split-type　photoelectrochemical　(PEC)　sensing　platform　for　prostate-specific　antigen　(PSA)　detection　was　successfully　constructed　using　p-type　Cu-doped　Zn0.3Cd0.7S　as　the　photosensitive　semiconductor　material　and　target-triggered　rolling　circle　amplification　(RCA)　for　signal　amplification.　The　signal　derived　from　Cu-doped　Zn0.3Cd0.7S　was　amplified　by　hemin/G-quadruplex.　Upon　target　PSA　introduction,　the　aptamer-primer　probe　(apt-pri)　was　captured　by　capture　antibody-conjugated　magnetic　bead　(MB-mAb)　to　form　the　sandwiched　MB-mAb/PSA/apt-pri.　The　complex　could　initiate　the　RCA　reaction　to　produce　a　long　single-stranded　DNA　that　provided　binding　sites　for　G-rich　DNA　and　to　form　long　single-stranded　DNA/G-quadruplex/hemin.　Upon　the　addition　of　exonuclease　III　(Exo　III),　the　hemin/G-quadruplex　immobilized　on　the　RCA　long　product　could　be　released　by　the　digestion　of　Exo　III.　The　hemin/G-quadruplex　complexes　in　this　study　were　used　as　efficient　electron　acceptors　to　neutralize　the　photoelectrons　generated　from　the　semiconductor　and　hindered　the　recombination　of　charges,　thus　enhancing　the　photocurrent.　Under　the　optimum　conditions,　the　developed　sensing　system　displayed　a　good　analytical　performance　with　a　linear　range　of　0.05-40　ng　mL(-1)　PSA　and　a　detection　limit　of　16.3　pg　mL(-1).　Furthermore,　good　selectivity,　high　anti-interference　ability,　satisfactory　reproducibility,　and　good　accuracy　were　also　achieved.　These　prominent　analytical　properties　revealed　that　our　strategy　might　be　a　potential　and　reliable　tool　for　the　detection　of　PSA.