A　simple　and　highly　sensitive　method　for　detection　of　miRNA　was　constructed　by　combining　the　high-efficiency　thiolated-mediated　strand　displacement　(TMSD)　non-enzymatic　amplification　and　the　high　-reproducibility　electrochemiluminescence/electrochemistry　(ECL/EC)　ratio　sensing　technique.　The　EC　signal　generated　by　methylene　blue　(MB)　modified　on　the　electrode　was　used　as　the　internal　reference　signal,　and　Ru(phen)(3)(2+)　was　embedded　in　DNA　nanoparticles　produced　by　the　branched　hybridization　chain　reaction　as　the　ECL　probe.　The　presence　of　target　miRNA　facilitated　the　detachment　of　MB　from　electrode　surface　and　the　modification　of　ECL　beacon　on　the　electrode,　resulting　in　a　decrease　of　the　EC　signal　and　an　enhancement　of　the　ECL　signal.　The　method　of　using　the　ratio　of　ECL　signal　to　EC　signal　reduced　potential　interference　and　improved　reproducibility　and　sensitivity　of　the　biosensor.　The　ratio　of　ECL/EC　signals　exhibited　linear　relationship　with　miRNA-21　concentration　in　the　range　from　10　fmol/L　to　500　pmol/L,　with　a　detection　limit　of　6.5　fmol/L,　and　the　relative　standard　deviation　of　the　assay　was　reduced　from　8.2　%　to　4.1　%　when　determining　1　pmol/L　target　miRNA-21　compared　to　that　using　single　ECL　signal.　This　method　was　preliminarily　applied　to　the　detection　of　miRNA-21　in　complex　cell　samples.