Infectious　diseases　are　a　long-standing　and　severe　global　public　health　problem.　The　rapid　diagnosis　of　infectious　diseases　is　an　urgent　need　to　solve　this　problem.　MicroRNA　(miRNA)　plays　an　important　role　in　the　intervention　of　some　infectious　diseases　and　is　expected　to　become　a　potential　biomarker　for　the　diagnosis　and　prognosis　of　infectious　diseases.　It　is　of　great　significance　to　develop　rapid　and　sensitive　methods　for　detecting　miRNA　for　effective　control　of　infectious　diseases.　In　this　study,　a　simple　and　highly　sensitive　homogeneous　electrochemical　method　for　microRNAs　using　enzyme-driven　cascaded　signal　amplification　has　been　developed.　In　the　presence　of　target　miRNA,　the　reaction　system　produced　plenty　of　MB-labeled　single-nucleotide　fragments　(MB-MF)　containing　a　few　negative　charges,　which　can　diffuse　to　the　negative　surface　of　the　ITO　electrode　easily,　so　an　obvious　electrochemical　signal　enhancement　was　obtained.　Without　the　target,　MB-HP　contains　a　relatively　large　amount　of　negative　charges　due　to　the　phosphates　on　the　DNA　chain,　which　cannot　be　digested　by　the　enzyme　and　cannot　diffuse　freely　to　the　negatively　charged　ITO　electrode,　so　only　a　small　signal　was　detected.　The　enhanced　electrochemical　response　has　a　linear　relationship　with　the　logarithm　of　miRNA　concentration　in　the　range　of　10 fM　to　10 nM　and　the　limit　of　detection　as　low　as　3.0 fM.　Furthermore,　the　proposed　strategy　showed　the　capability　of　discriminating　single-base　mismatch　and　performed　eligibly　in　the　analysis　of　miRNA　in　cell　lysates,　exhibiting　great　potential　for　disease　diagnosis　and　biomedical　research.　[Figure　not　available:　see　fulltext.]　©　2020,　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.