Portable　and　on-site　detection　of　target　biomarker　is　of　great　significance　in　early　diagnosis　of　diseases.　Herein,　we　designed　a　portable　smartphone-based　PEC　immunoassay　platform　to　detect　prostate　specific　antigen　(PSA)　adopting　Co-doped　Bi2O2S　nanosheets　as　photoactive　materials.　The　fast　photocurrent　response　under　visible　light　and　excellent　electrical　transport　rate　invest　Co-doped　Bi2O2S　with　the　property　of　being　effectively　excited　even　under　a　weak　light　source.　Therefore,　with　the　incorporation　of　a　carriable　flashlight　that　act　as　the　excitation　light　source,　disposable　screen-printed　electrodes,　a　microelectrochemical　workstation　and　a　smartphone　that　served　as　control　center,　point-of-care　analytical　detection　of　low-abundance　small　molecule　analytes　was　successfully　realized.　Specifically,　a　sandwich-type　immunoreaction　was　performed　using　alkaline　phosphatase　labeled　secondary　antibody　as　signal　indicator.　In　the　presence　of　PSA,　ascorbic　acid　as　generated　through　a　catalytic　reaction,　resulting　in　the　enhancement　of　photocurrent　intensity.　The　photocurrent　intensity　increased　linearly　with　the　logarithm　of　PSA　concentrations　ranging　from　0.2　to　50　ng　mL−1　with　a　detection　limit　of　71.2　pg　mL−1　(S/N　=　3).　This　system　provided　an　effective　method　for　the　construction　of　portable　and　miniaturized　PEC　sensing　platform　for　the　application　of　point-of-care　health　monitoring.　©　2023　Elsevier　B.V.