The　difference　of　electrostatic　interaction　between　free　Ru(phen)(3)(2+)　and　Ru(phen)(3)(2+)　embedded　in　double　strand　DNA　(dsDNA)　to　the　negatively　charged　indium　tin　oxide　(ITO)　electrode　has　been　applied　to　develop　a　homogeneous　and　label-free　electrochemiluminescence　(ECL)　aptasensor　for　the　first　time.　Ochratoxin　A　(OTA)　has　been　chosen　as　the　model　target.　The　OTA　aptamer　is　first　hybridized　with　its　complementary　single　strand　DNA　(ssDNA)　to　form　dsDNA　and　then　interacted　with　Ru(phen)(3)(2+)　via　the　grooves　binding　mode　to　form　dsDNA-Ru(phen)(3)(2+)　complex,　which　remains　negatively　charged　feature　as　well　as　low　diffusion　capacity　to　the　negatively　charged　ITO　electrode　surface　owing　to　the　electrostatic　repulsion.　Meanwhile,　the　intercalated　Ru　(phen)(3)(2+)　in　the　grooves　of　dsDNA　works　as　an　ECL　signal　reporter　instead　of　the　labor-intensive　labeling　steps　and　can　generate　much　more　ECL　signal　than　that　from　the　labeling　probe.　In　the　presence　of　target,　the　aptamer　prefers　to　form　an　aptamer-target　complex　in　lieu　of　dsDNA,　which　induces　the　releasing　of　Ru(phen)(3)(2+)　from　the　dsDNA-Ru(phen)(3)(2+)　complex　into　the　solution.　With　the　assistance　of　RecJ(f)　exonuclease　(a　ssDNA　specific　exonuclease),　the　released　ssDNA　and　the　aptamer　in　the　target-complex　were　digested　into　mononucleotides.　In　the　meantime,　the　target　can　be　also　liberated　from　OTA-aptamer　complex　and　induce　target　cycling　and　large　amount　of　free　Ru(phen)(3)(2+)　present　in　the　solution.　Since　Ru(phen)(3)(2+)　contains　positive　charges,　which　can　diffuses　easily　to　the　ITO　electrode　surface　because　of　electrostatic　attraction,　causing　an　obviously　enhanced　ECL　signal　detected.　Under　the　optimal　conditions,　the　enhanced　ECL　of　the　system　has　a　linear　relationship　with　the　OTA　concentration　in　the　range　of　0.01-1.0　ng/mL　with　a　detection　limit　of　2　pg/mL.　This　innovative　system　not　only　expands　the　immobilization-free　sensors　in　the　electrochemiluminescent　fields,　but　also　can　be　developed　for　the　detection　of　different　targets　easily　with　the　same　strategy　by　changing　the　aptamer　used.