This　work　designed　a　new　photoelectrochemical　(PEC)　immunoassay　for　the　ultrasensitive　detection　of　alpha-fetoprotein　(AFP)　based　on　the　flower-like　β-In2S3@carbon　dots　(CDs).　The　photocurrent　of　the　as-prepared　heterogeneous　nanostructure　was　enhanced　significantly　under　ultraviolet　(UV),　visible　(Vis)　and　near-infrared　(NIR)　irradiation　thanks　to　the　more　generation　of　carriers　and　less　electron-hole　pairs　recombination　with　CDs.　The　three-layer　sandwich-like　immunocomplex　would　be　formed　upon　the　target　AFP　existed,　the　ascorbic　acid　2-phosphate　(AA2P)　was　subsequently　transformed　into　ascorbic　acid　(AA)　owing　to　the　catalysis　of　alkaline　phosphatase-conjugated　rabbit　polyclonal　anti-human　AFP　(ALP-Ab2).　Without　additional　applied　voltage,　the　photocurrent　of　the　β-In2S3@CDs-modified　electrode　was　positively　correlated　with　the　increasing　AA　level　in　the　detection　cell.　Under　optimal　conditions,　the　developed　PEC　immunosensing　platform　exhibited　good　reproducibility　and　high　sensitivity　for　the　determination　of　target　AFP　within　a　dynamic　working　range　from　0.5　to　50　ng　mL−1　at　a　detection　limit　of　37.9　pg　mL−1.　In　addition,　the　method　accuracy　relative　to　human　AFP　ELISA　kit　was　evaluated　by　analyzing　human　serum　specimens,　and　a　good　match　between　two　methods　was　obtained.　Such　the　increasing　photocurrent　through　full-spectrum　responsive　mode　gives　a　new　horizon　to　develop　highly　sensitive　PEC　immunoassay　in　early　clinical　diagnosis　by　monitoring　disease-related　biomarkers.　©　2019　Elsevier　Ltd