A　DNA　molecular　switch　fluorescence　sensor　based　on　hairpin　triple　helix　structure　was　designed　to　achieve　simultaneous　sensitive　determination　of　two　target　antibiotics　by　aptamer　specific　recognition.　The　molecular　switching　structure　consists　of　a　specific　aptamer　recognition　sequence　and　a　double-labeled　signal　probe　sequence.　The　two　ends　of　the　signal　probe　for　tetracycline　recognition　were　modified　with　pyrene　molecules,　and　the　two　ends　of　the　signal　probe　for　chloramphenicol　recognition　were　modified　with　cadmium　sulfide　quantum　dots　(CdS　QDs)　and　gold　nanoparticles,　respectively.　The　aptamer　sequence　was　inserted　into　the　loop　region　to　form　a　three-chain　structure.　When　the　target　antibiotic　was　present,　the　recognition　probe　bound　to　it　and　released　a　signal　probe,　bringing　the　luminescent　substance　at　both　ends　closer　together,　and　the　fluorescence　signal　changed　significantly　(enhanced　or　reduced).　The　fluorescence　intensity　of　the　sensor　showed　a　good　linear　relationship　with　the　concentrations　of　tetracycline　and　chloramphenicol,　the　linear　range　was　1×10-3-10　μmol/L,　and　the　detection　limit　was　0.3　nmol/L.　The　method　was　used　to　determine　tetracycline　and　chloramphenicol　in　eggs　with　satisfactory　results.　©　2023,　Youke　Publishing　Co.,Ltd.　All　rights　reserved.