The most common malignant brain tumor is intracranial glioma. Gliomas are classified as grade I, II, III and IV gliomas in descending order of malignancy. Grade I gliomas are benign, and if the tumor can be completely removed by surgery, the tumor will not recur after surgery, and the patient can achieve the purpose of cure. Grade II, III and IV gliomas are malignant gliomas, which have no obvious boundary with the surrounding brain tissue and are infiltrative in growth. Grade IV glioma, also known as glioblastoma, has the highest malignancy. Even with surgery plus radiotherapy, its average survival is only about 12-14 months. If left to develop without surgery, the patient will die in about 3 months.