Abstract: Gliomas, the most common type of primary brain tumor, have various subtypes and a wide range of prognoses. They are difficult to safely surgically resect and have limited treatment options owing to their awkward location. In the era of precision medicine, identifying tumor driver genes or driver mutations and analyzing specific DNA mutation patterns are key to therapy for difficultto-treat cancers. Tumor biopsies reveal results from a single site at a single time point and therefore may be inadequate for characterizing the heterogeneity and dynamic evolution of the genomic landscape. In contrast, circulating tumor DNA (ctDNA) can be used to noninvasively monitor tumor genomes and provide accessible genetic biomarkers for diagnosing cancer, monitoring response to therapy, and providing a prognosis. This study evaluated the research progress on ctDNA in gliomas and systematically reviewed the following topics: ctDNA detection methods, ctDNA as a reflection of the heterogeneity of tumors, the use of ctDNA for early diagnosis, and the use of ctDNA for monitoring tumor mutation burden and response to treatment.