Detection　of　well-studied　cancer　biomarkers　of　microRNAs　(miRNAs)　is　very　valuable　for　early　cancer　diagnosis　and　therapy　in　clinical　medicine.　Herein,　we　designed　a　binary　C-rich　functionalized　palindromic　hairpin　probe　(BC-FPHP)　and　employed　it　as　the　only　species　to　amplify　the　common　ovarian　cancer　biomarker　of　miRNA-21.　The　BC-FPHP　is　concurrently　proposed　with　a　miRNA-21　recognition　loop　region,　a　self-complementary　stem　region,　a　binary　C-rich　fragment　at　its　5＇　end,　and　a　palindromic　sequence　at　its　3＇　end.　The　presence　of　target　miRNA-21　induces　the　configuration　change　of　BC-FPHP.　It　makes　the　amplification　event　on　BC-FPHP　occurred　without　the　aid　of　any　other　probes,　leading　to　a　substantial　collection　of　binary　G-quadruplex　DNA　motifs　that　can　be　inserted　with　thioflavin　T　(ThT)　for　remarkable　fluorescence　emission.　In　this　system,　the　BC-FPHP　is　smartly　designed　with　the　capabilities　to　be　self-primered,　self-templated,　and　self-amplified,　ensuring　the　isothermal　amplification　system　a　simple,　low　cost,　and　user-friendly　detection　platform　for　sensitive　and　specific　detection　of　miRNA-21.　In　addition,　the　BC-FPHP　based　amplification　system　has　been　successfully　used　for　the　detection　of　miRNA-21　in　diluted　human　serum　samples.　We　envision　that　this　work　holds　great　potential　in　the　early　assisting　screening　of　ovarian　cancer.