Primary central nervous system lymphoma (PCNSL) is a rare and special kind of non-Hodgkin lymphoma. Chemotherapy based on high-dose methotrexate (HD-MTX) is considered a standard therapy for newly diagnosed PCNSL, but the prognosis of PCNSL is poor due to its high invasiveness and recurrence rate. Risk stratification and prognosis assessment of PCNSL in diagnosis is particularly important in clinical treatment. At present, MSKCC (the Memorial Sloan Kettering Cancer Center), the International Extranodal Lymphoma Study Group (IELSG) and Nottingham/Barcelona scoring models are mostly used to classify the risk and evaluate the prognosis of PCNSL. With the further understanding of immunohistochemistry and molecular genetics of PCNSL, potential prognostic factors continue to emerge.