The　analysis　and　detection　of　telomerase　activity　is　important　for　cancer　diagnosis，prog⁃　nosis，and　treatment.　In　this　study，an　electrochemiluminescence（ECL）　biosensor　was　constructed　for　sensitive　detection　of　telomerase　activity　in　cancer　cells　using　a　metal　complex-targeted　luminescent　probe［Ir（ppy）2（pip）］PF6　for　G-quadruplex（G4）　DNA.　Primer　DNA　was　first　assembled　on　the　electrode　surface　and　then　co-incubated　with　telomerase　extracted　from　cancer　cells.　The　active　telomerase　generated　telomeric　repeats　at　the　end　of　the　primer　to　form　the　G4　structure，and　then［Ir　（ppy）2（pip）］PF6　bound　to　the　extended　sequence　by　targeting　with　G4.　The　results　showed　that　the　ECL　signal　of［Ir（ppy）2（pip）］PF6　showed　a　positive　correlation　with　telomerase　activity，　and　the　ECL　intensity　of　the　sensor　showed　a　good　linear　correlation　with　the　concentration　of　cancer　cells　in　the　range　of　10-5×105　cell/mL，with　the　limit　of　detection（LOD）　of　3　cell/mL.　The　experiments　also　demonstrated　that　the　sensor　had　good　stability，　applicability，　anti-interference　ablity，　and　reproducibility.　Finally，the　sensor　was　used　for　the　determination　of　telomerase　activity　in　real　human　serum　and　urine　samples，and　satisfactory　results　were　also　obtained.　©　2024,　J.　Instrum.　Anal.　All　rights　reserved.