A　highly　sensitive　and　specific　visual　detection　method　for　aflatoxin　B1　(AFB1)　based　on　the　target　specificity　of　aptamer,　rolling　circle　amplification　(RCA)　and　enzyme　catalysis　biological　amplification　effect　has　been　established.　In　this　work,　AFB1　aptamer　immobilized　on　the　surface　of　magnetic　beads　(MB)　serves　as　a　molecular　recognition　probe.　In　the　absence　of　AFB1,　the　aptamer　and　auxiliary　linking　probe　(LP)　maintain　a　double　stranded　state　due　to　partial　base　pair　complementarities.　By　contrast,　in　the　presence　of　AFB1,　the　aptamer　preferentially　binds　to　AFB1　specifically,　and　the　LP　later　restores　to　a　single　stranded　state.　Subsequently,　the　RCA　reaction　is　triggered　by　above-mentioned　single　stranded　LP　to　generate　long　DNA　strands,　which　are　employed　to　capture　amounts　of　signal　probes　(SP)　and　horse　radish　peroxidases　(HRP).　Finally,　amounts　of　HRP　catalyze　the　oxidation　of　3,3′,5,5′-tetramethylbenzidine　(TMB)　by　H2O2　and　leads　to　a　dramatic　color　change　of　the　solution　from　colorlessness　to　deep　blue　as　a　signal　indicator,　obtaining　a　high　sensitivity,　high　specificity　and　visual　detection　of　AFB1.　Under　optimal　conditions,　a　good　linear　detection　range　(0.5–40　pg·mL−1)　was　achieved,　and　the　limit　of　detection　(LOD)　was　0.13　pg·mL−1.　Besides,　the　proposed　aptasensor　showed　excellent　specificity　for　AFB1　compared　with　five　other　mycotoxins.　More　than　that,　all　reactions　occur　on　the　surface　of　the　magnetic　beads,　which　not　only　facilitates　the　detection　operation　process　including　the　efficient　isolation　and　collection　of　AFB1　from　sample　matrix,　but　also　gets　better　selectivity　and　stronger　resistibility　to　target　analyte　in　complex　sample　matrix,　adequately　indicating　its　potential　application　in　AFB1　practical　detection.　©　2022