The　low　concentration,　high　sensitivity　and　non-toxicity　of　co-reactant　in　electrochemiluminescence　(ECL)　systems　are　the　key　factors　for　the　application　in　life　analysis.　Cysteamine　(CS),　a　substance　produced　in　the　body　of　life　,　was　used　as　the　co-reactant　to　investigate　the　ECL　property　of　Ru　(bpy)(3)(2+)　ECL　system　in　this　work.　The　results　showed　that　CS　as　a　co-reactant　could　significantly　enhance　the　anodic　ECL　signal　of　Ru　(bpy)(3)(2+)　under　neutral　environment.　The　influences　of　experimental　conditions　including　CS　concentration,　Ru　(bpy)(3)(2+)　concentration,　pH　value　of　buffer　solution　and　other　factors　on　ECL　signal　of　the　system　were　studied,　and　the　mechanism　of　the　novel　ECL　system　was　discussed.　Based　on　the　ECL　signal　of　Ru　(bpy)(3)(2+)-CS　system　quenching　by　hydrogen　peroxide　under　optimal　experimental　conditions,　the　sensitive　determination　of　hydrogen　peroxide　was　achieved　with　a　linear　range　of　5　x　10(-8)-5　x　10(-5)　mol/L　and　a　limit　of　detection　of　10　nmol/L　(S/N=　3).　In　view　of　the　good　biocompatibility　and　non-toxicity　of　CS,　as　well　as　the　excellent　ECL　enhancement　efficiency,　this　ECL　system　had　significant　application　potential　in　biological　analysis.