The　development　of　a　versatile　biosensing　platform　to　screen　specific　DNA　sequences　is　still　an　essential　issue　of　molecular　biology　research　and　clinic　diagnosis　of　genetic　disease.　In　this　work,　we　for　the　first　time　reported　a　double-stem　hairpin　probe　(DHP)　that　was　simultaneously　engineered　to　incorporate　a　DNAzyme,　DNAzyme＇s　complementary　fragment　and　nicking　enzyme　recognition　site.　The　important　aspect　of　this　hairpin　probe　is　that,　although　it　is　designed　to　have　a　long　ds　DNA　fragment,　no　intermolecular　interaction　occurs,　circumventing　the　sticky-end　pairing-determined　disadvantages　encountered　by　classic　molecular　beacon.　For　the　DHP-based　colorimetric　sensing　system,　as　a　model　analyte,　cancer-related　DNA　sequence　can　trigger　a　cascade　polymerization/nicking　cycle　on　only　one　oligonucleotide　probe.　This　led　to　the　dramatic　accumulation　of　G-quadruplexes　directly　responsible　for　colorimetric　signal　conversion　without　any　loss.　As　a　result,　the　target　DNA　is　capable　of　being　detected　to　1　fM　(six　to　eight　orders　of　magnitude　lower　than　that　of　catalytic　molecular　beacons)　and　point　mutations　are　distinguished　by　the　naked　eye.　The　described　DHP　as　a-proof-of-concept　would　not　only　promote　the　design　of　colorimetric　biosensors　but　also　open　a　good　way　to　promote　the　diagnosis　and　treatment　of　genetic　diseases.