Graphitic nanomaterial, which has unique optical properties, attracts extensive attention in biochemical sensing. Herein, we summarize and discuss the recent progress of such material as a optical probe,photothermal material and signal transduction substrate for biosensing applications, respectively. The most attracting optical property of graphitic nanomaterial is its strong and unique Raman signals. As a Raman probe, it has remarkable applications, especially in detecting complex biological samples, quantitative SERS detection, and detection under extreme conditions. Except for Raman, the unique intrinsic fluorescence emission of single-walled carbon nanotubes (SWNTs) in the long wavelength, second near-infrared window (NIR-II window, 1000-1700 nm) has allowed for deep-tissue high-resolution fluorescence imaging in vivo. On the other side, graphitic nanomaterial has efficient photothermal conversion capability. Together with the large surface area, graphitic nanomaterials are used in the photothermal synergy therapy for cancer treatments. Furthermore, because of its particular physical and chemical properties, graphitic nanomaterial is established as an efficient signal transduction substrate, which could quench excited chromophore and photosensitizer, showing high selectivity and sensitivity in biosensing and nanomedicine.