There are primary and secondary CNS lymphomas. Primary refers to lymphomas that occur only in the CNS, accounting for approximately 0.2-2% of primary intracranial tumors, with occasional extracranial metastases, while secondary refers to systemic lymphomas that metastasize to the CNS, with approximately 1-7% of systemic lymphomas metastasizing intracranially at later stages of treatment. The incidence of primary CNS lymphoma is much more frequent than secondary ones in clinical practice. From reported data in Europe and the United States, the incidence of primary central nervous system lymphoma (hereafter referred to as lymphoma) has been gradually increasing over the past 20 years, and in some countries has approached the incidence of meningioma and low-grade astrocytoma, which may be related to the increasing number of AIDS and organ transplantation year by year. The ratio of men to women is roughly 1.5:1, and the age of onset is around 50 years, while those occurring in younger people are mostly associated with the presence of immunosuppressive diseases. The common sites of occurrence of lymphoma are mostly located in the frontal lobes, basal ganglia and periventricular areas of the brain, but sometimes they also occur in the cerebellum. Clinical symptoms and presentation are not very different from those of other intracerebral tumors and are not specific. Pathologically, lymphomas are subdivided into B-cell and T-cell types, with the B-cell type being more common. The imaging diagnosis of lymphoma mainly relies on cranial CT and MRI. On enhancement scans, more than 90% of lymphomas appear as enhancing mass-like lesions in the brain, and more than 70% of enhancements are homogeneous, which some people image as “flully cotton balls”. If the lesion is adjacent to the ventricular canal or soft meninges, there may also be simultaneous enhancement of the ventricular canal or soft meninges, which is easily confused with meningioma. After steroid hormone administration, the lymphoma tends to shrink significantly or even disappear, so some people abroad call it “ghost-cell tumor”. The treatment of lymphoma mainly includes surgery, chemotherapy and radiotherapy, and now there is also gene targeted therapy. The purpose of surgery is to obtain diseased tissue for pathological histological examination to clarify the diagnosis. For deep brain tumors stereotactic biopsy surgery is most appropriate. Tumor resection and decompression should also be considered for the occurrence of severe intracranial hypertension and brain herniation crisis. Intravenous application of high-dose methotrexate (MTX) chemotherapy is the main option for the treatment of lymphoma. In special cases, transcranial MTX chemotherapy can also be considered, and these chemotherapies need to be administered by specialized physicians. In cases where chemotherapy is not effective, whole brain radiotherapy can be considered, but the dose tends to be lower than for other brain tumors, with 40-50 Gy being appropriate and a split dose of 1.8-3.0 Gy. In recent years, additional gene targeted therapy drugs for lymphoma have emerged, and the only one available on the market now is melphalan, a rituximab injection for the treatment of relapsed or chemotherapy-resistant inert B-cell non- Hodgkin’s lymphoma. As for the efficacy of melova in treating CNS lymphoma, it is all still under continued observation. The prognosis of lymphoma is highly variable, with survival after diagnosis often ranging from 1.8-3.3 months if no treatment is received. The average survival for those receiving radiotherapy alone is 10 months, 47% for more than one year, 16% for more than two years, 8% for more than three years, and 3-4% for more than five years. For those who undergo MTX chemotherapy, the tumor tends to relapse at an average of 41 months, however, some cases with very long survival have now been identified. In conclusion, the treatment of lymphoma should be based on the specific conditions of the patient and the tumor, and the appropriate protocol should be used. From our clinical observation, the treatment effect of lymphoma has now been significantly improved, and the survival period of patients has been significantly extended.