Objective Glioma is the most common malignant primary tumor of the central nervous system. Recently, the rapid development of molecular pathology has brought an important influence on the diagnosis and classification of gliomas. The latest version of the World Health Organization (WHO) Classifications of The Central Nervous System Tumors (fifth edition) published in 2021 has introduced more molecular features to guide the diagnosis and classification of gliomas. The aim of this study was to provide evidence of the application of the latest version of WHO classification via comparing the fluences of the latest and the previous version of WHO classifications on tumor diagnosis and prognosis in a clinical cohort.Methods 512 glioma samples were retrospectively included in the cancer genome atlas database. The diagnosis was performed according to the latest (2021 edition) and the previous version (2016 edition) of WHO classifications, respectively. Kaplan-Meier curves were used to calculate median overall survival and analyze survival differences.Results We completed the diagnosis and grading of 512 cases by the latest (2021 edition) and the previous version (2016 edition) of WHO classifications, respectively. 53 cases of IDH mutant tumors and 72 cases of IDH wildtype tumors were upgraded to grade 4 in the latest version (2021 edition) of the WHO classification. These tumors with elevated grades also had a worse prognosis.Conclusion Compared with the previous version, glioma can be classified and graded more accurately by the latest version (2021 edition) of the WHO classification. Diagnosis and grading should be performed according to the latest version as soon as possible.