Membrane　proteins　play　crucial　roles　in　cellular　activities　and　are　the　major　actors　of　bio-membrane　functions.　Programmed　death　ligand　receptor　1　(PD-L1)　is　a　type　of　transmembrane　protein　that　is　overexpressed　on　certain　tumor　cells,　leading　to　the　immune　escape　of　cancer　cells.　Here,　a　detection　method　was　developed　using　scanning　electrochemical　microscopy　(SECM)　through　aptamer-specific　recognition　and　enzyme-catalyzed　reaction,　which　converts　the　PD-L1　expression　into　an　electrical　signal.　The　aptamer　(MJ5C)　modified　alkaline　phosphatase　(ALP)　can　specifically　capture　PD-L1,　and　ALP　catalyzes　the　reduction　of　4-aminophenyl　phosphate　(PAPP)　to　p-aminophenol　(PAP),　the　current　response　of　PAP　at　SECM　tip　is　positively　correlated　with　the　expression　of　PD-L1　on　NCI-H1975　cell.　The　results　showed　that　this　method　could　real-time　detect　the　expression　of　PD-L1　on　a　single　cell　stimulated　by　drugs　and　dibenzothiophene　(DBT).　Overall,　this　method　provides　a　new　feasible　method　for　the　real-time　nondestructive　detection　of　single-cell　membrane　protein　expression　and　a　new　avenue　for　studying　the　effect　of　pollutants　on　membrane　protein.　©　2025　Elsevier　B.V.