Herein　a　versatile　photoelectrochemical　(PEC)　bioanalysis　platform　for　sensitive　and　specific　screening　of　low　abundance　antibiotics　(kanamycin,　Kana,　used　in　this　case)　was　innovatively　designed　using　rGO-Bi2WO6-Au　as　photoactive　matrix　and　target-induced　branched　hybridization　chain　reaction　(t-bHCR)　for　efficient　signal　amplification.　To　realize　the　high-performance　of　our　PEC　bioanalysis　system,　rational　introduction　of　reduced　graphene　oxide　(rGO)　and　Au　nanoparticles　(Au　NPs)　greatly　accelerated　the　electron　transfer　and　enhances　photoactivity.　As　expected,　the　ternary　nanocomposite　(i.e.,　rGO-Bi2WO6-Au)　system　with　cascade　energy　level　exhibited　intense　PEC　signal　responses　thanks　to　multistep　electron-transfer　(MET)　mechanism.　Upon　sensing　the　target　Kana,　t-bHCR　is　readily　implemented,　thus　resulting　in　the　assembly　of　numerous　CuS　nanoparticle　(CuS　NP).　As　a　result,　the　loading　CuS　NPs　from　hyper-branched　structure　boosted　the　electron　donors　(ascorbic　acid)　consumption　and　enhanced　the　steric　hindrance,　synergistically　decrease　the　photoelectric　response.　Under　the　optimized　testing　conditions,　the　t-bHCR-based　PEC　bioanalysis　exhibited　superior　analytical　performance　with　a　linear　range　of　1　pM　to　5　nM　target　Kana　and　limit　of　detection　down　to　0.78　pM.　Additionally,　favorable　stability,　great　anti-interference　ability　and　satisfactory　accuracy　for　the　analysis　of　actual　samples　were　acquired.　Impressively,　the　concept　of　t-bHCR-mediated　provides　an　alternative　to　construct　PEC　bioanalysis　and　inspire　more　interest　in　the　design　of　advanced　PEC　bioanalysis　through　nucleic　acid-related　signal　amplification.