The length of time a patient with malignant brain tumor can live cannot be generalized and is closely related to the type of tumor, treatment and the patient’s underlying health status. There are two types of malignant brain tumors: primary and secondary. Primary brain tumors are more commonly known as gliomas, which are classified into grade I-IV according to their malignancy, and those with higher malignancy are more difficult to cure. Secondary brain tumor refers to the metastasis of tumors from other parts of the brain, and the survival of such patients is mostly related to their overall condition. Generally speaking, brain metastasis from other cancers, if left untreated, has a poorer prognosis and a shorter survival period. As for the specific survival time, it needs to be evaluated by the treating physician in combination with the patient’s cancer type, the degree of metastasis, and treatment modality. Therefore, patients with malignant brain tumor are recommended to actively visit the medical oncology department of regular hospitals and be actively treated by professional doctors after clarifying the specific condition. After treatment, patients should also insist on regular follow-up to understand the changes of the disease so as to facilitate timely and targeted treatment.