Carbon dot (CD)-based tumor imaging has been proven to be a reliable nanodiagnostic technique. Although abundant types of CDs have been developed, it is still a major challenge to synthesize long-wavelength CDs with high quality and superior repetition due to the complicated synthetic process. Here, stable long-wavelength red-light emission carbon dots (R-CDs) have been synthesized using appropriate carbon sources via a solvothermal method, which enables effective visualization of deep brain glioblastoma (GBM) by a liposome-formulated delivery system. The luminescence phenomenon and structural growth characteristics of R-CDs have been fully investigated and it has been found that R-CDs exhibit different optical behaviors in different pH and solvent environments. In vitro and in vivo models have proved their excellent cell targeting capacity, bioluminescence imaging potential, and biosafety for GBM visualization. Considering their stability and biocompatibility, the in-depth tissue imagining and other extensive applications of R-CDs are strongly recommended.