A　novel　aptamer-functionalized　metal-organic　framework　nanofibrous　composite　(viz.　PAN/UiO@UiO2-N3-aptamer)　with　a　high　aptamer　coverage　density　was　proposed　based　on　the　electrospinning　and　seeded　growth　method,　and　used　for　specific　affinity　recognition　of　trace　Microcystin-LR　(MC-LR).　Heterobifunctional　ligand　was　used　to　modify　the　metal–organic　framework　nanoparticles　(MOF　NPs)　surface,　which　could　passivate　the　MOF　surface　with　respect　to　unmodified　DNA,　followed　by　coupling　massive　aptamers　on　MOF　of　the　solid-phase　microextraction　(SPME)　fiber　using　click　chemistry.　Characterizations　including　morphology,　spectra　analysis,　mechanical　stability,　binding　capacity　and　specificity　were　fulfilled.　Applied　to　the　analysis　of　MC-LR,　the　good　selective　and　sensitive　recognition　were　obtained　with　the　detection　limit　as　low　as　0.003　ng/mL,　which　was　better　than　most　non-specific　SPME　or　solid-phase　extraction　(SPE)　protocols.　The　stability　and　reproducibility　were　acceptable,　and　the　intra-day,　inter-day　and　column-to-column　relative　standard　deviations　(RSDs)　for　the　recovery　of　MC-LR　were　gained　in　the　range　from　2.5%　to　14.3%,　respectively.　Satisfactory　recoveries　of　MC-LR　in　environmental　water　samples　were　measured　as　96.3　±　4.7%　-　98.9　±　2.7%　(n　=　3)　in　tap　water,　94.4　±　2.5%　-　96.1　±　3.5%　(n　=　3)　in　pond　water,　and　97.0　±　2.1%　-　97.9　±　3.1%　(n　=　3)　in　river　water,　respectively.　This　work　demonstrated　that　the　electrospun　nanofibrous　composite　with　massive　aptamers　would　be　a　better　alternative　for　ultra-trace　MC-LR　detection　with　good　selectivity,　matrix-resistance　ability　and　high　resolution.　©　2021