Methods　derived　from　photoelectrochemical　(PEC)　have　been　constructed　for　immunoassays,　but　most　involve　the　split-type　immunoreaction　modes,　and　thus　easily　cause　unpredictable　intermediate　precision.　Herein,　we　innovatively　designed　an　integrated　PEC　immunosensing　platform　for　the　quantitative　monitoring　of　thyroglobulin　(TG)　on　the　gold　nanoparticles　(AuNPs)-functionalized　BiVO4　photoanode　coupling　with　enzymatic　biocatalytic　precipitation　(EBCP).　This　sensing　system　could　simultaneously　implement　the　immunoreaction　and　photocurrent　measurement.　Anti-TG　capture　antibodies　were　modified　onto　AuNPs-decorated　BiVO4　photoelectrode.　A　sandwich-type　immunoreaction　was　carried　out　in　the　presence　of　target　TG　using　horseradish　peroxidase　(HRP)-conjugated　anti-TG　detection　antibody.　The　carried　HRP　molecules　catalyzed　4-chloro-1-naphthol　(4-CN)　to　generate　an　insoluble　benzo-4-chlorohexadienone　product　on　the　photoanode　in　the　presence　of　peroxide　hydrogen,　thereby　decreasing　the　photocurrent.　Under　optimal　conditions,　the　PEC　immunosensors　gave　good　photocurrent　responses　toward　target　TG　within　the　dynamic　range　of　0.01–10　ng　mL−1　at　a　detection　limit　of　7.6　pg　mL−1.　Good　repeatability　and　precision,　high　specificity　and　acceptable　storage　stability　were　acquired　during　the　measurement.　No　significant　differences　were　encountered　for　screening　15　human　serum　specimens　between　the　developed　PEC　immunoassay　and　commercially　available　enzyme-linked　immunosorbent　assay　(ELISA)　method　for　the　detection　of　target　TG.　Significantly,　PEC　immunosensing　system　offers　promise　for　simple　and　cost-effective　analysis　of　disease-related　biomarkers.　©　2022　Elsevier　B.V.