Intracranial metastases (BM) are one of the most important complications in cancer patients, and about 20% to 40% of patients with malignant tumors will develop brain metastases. Currently, intracranial metastases are mainly treated by surgery and stereotactic radiotherapy (SRT). The purpose of surgical treatment is to control the progression of brain tumor, relieve the neurological symptoms of patients, and provide accurate molecular characteristics of the tumor. The indications include the following three aspects: (1) Therapeutic: lesions >3 cm in size, symptomatic or asymptomatic; cystic lesions or necrotic lesions accompanied by edema; symptomatic lesions located in important areas; lesions located in the posterior fossa of the skull, accompanied by space-occupying effects or hydrocephalus. (2) Diagnostic: Unclear primary cancer lesion; potential differential diagnosis; suspected radionecrosis in patients who have had prior radiotherapy. (3) Adjuvant treatment strategy development: molecular biological characterization for patients who may undergo novel targeted therapies. A variety of factors need to be considered, including the patient’s clinical factors and functional status, systemic diseases, and intracranial metastases. Clinical factors and functional status of patients: BM patients undergoing surgery need to be in relatively good general condition and free of major cardiovascular and pulmonary diseases; the Karnofsky index is an important factor in making decisions about localized treatment, and when the Karnofsky functional status (KPS) score is <70, it implies that the patient's prognosis is poor, and the rationality of surgical treatment should be carefully considered. Rationalization. Systemic disease: Control of the primary tumor lesion and extracranial metastases is also an important factor in the choice of treatment. Systemic disease is an important prognostic factor for patients with BM. Several studies have shown that control of systemic disease has a positive impact on the overall survival of surgically resected BM patients. Intracranial metastases: Initially, surgical resection of intracranial metastases was limited to a single lesion; however, as technology has improved, the use of surgery combined with adjuvant whole brain radiation therapy (WBRT) for multiple metastases is now supported. 3.New surgical indications in targeted therapy More and more studies are now focusing on the potential phenotypic heterogeneity of tumors in order to assist clinicians in making better treatment decisions. The biological typing of brain metastatic tumors has also led to a shift in therapeutic approaches. Since 2012, several studies have explored the efficacy of targeted therapy based on molecular typing compared with conventional therapy for BM. Although the two previous large-scale studies did not show results in favor of targeted therapy, there is no doubt that targeted therapy is the future direction of development. Stereotactic radiation therapy (SRT) is a "high-precision" radiation therapy technique (the range can be accurate to within 1 mm), which uses different machine-assisted, high-dose (4-25 Gy) radioactive element irradiation; it can minimize the damage to the surrounding healthy tissue. The choice of SRT type depends on the number, size and location of the BMs. SRT may be considered: (1) in patients in good general condition with 1-3 BM lesions and well-controlled extracranial lesions, in combination with WBRT to improve survival; (2) in patients with 1-3 BM lesions that recur after WBRT; (3) in patients with symptomatic BM after complete surgical resection; (4) in patients with 3-5 asymptomatic BM lesions that occur in the course of systemic therapy; (5) in patients with BM in the course of systemic therapy. (4) in patients with 3-5 asymptomatic lesions or progressive BM during systemic therapy. SRT alone, without surgery and WBRT: generally used in patients with well-controlled extracranial tumors, few or basically asymptomatic symptoms, limited number of metastatic tumors (max. 4-5), and volume <3 3="" cm="" srt="" mri="">3 cm, cystic lesions or edema around the lesions, obvious symptoms or lesions that have a significant impact on function. impact in patients. The condition of the extracranial tumor is not the most important consideration, and the primary goal of this treatment approach is to improve control of the intracranial lesion as well as to improve the quality of the patient’s prognosis. SRT in combination with WBRT or WBRT followed by SRT: This treatment may be considered when the number of metastatic lesions is 2-3, and is effective in improving survival compared with WBRT alone. It is especially suitable for patients with small cell lung cancer, DS-PGA score ≥3, and brain metastasis. Low-fraction stereotactic radiotherapy High-dose (15-25 Gy) radiotherapy to a single lesion results in a greatly increased risk of radionecrosis, and the risk is higher when the tumor diameter exceeds 25-30 mm or when it is near sensitive tissues or organs. In such cases, the use of hypofractionated stereotactic radiotherapy (HSRT) may be a good choice, which helps to reduce the risk of radionecrosis while maintaining better lesion control. Through the literature review, the author believes that the best indications and methods for HSRT are: BM lesions with a diameter of more than 25 mm, up to 35-40 mm; 3-5 irradiations, each with a dose of 7-8 Gy (up to 11-12 Gy), and the overall equivalent dose of irradiation is 70%-80% of the original dose. Radiation necrosis can occur 6-12 months after SRT treatment, and its incidence varies from 2% to 22%; the proportion of patients with symptoms is 1% to 14%. Cranial MRI shows “crown-like” enhancement on T1 images and edema around the lesion on FLAIR images, but these manifestations are not specific. Since many patients are asymptomatic, a detailed clinical evaluation is important. There is no curative treatment for radionecrosis. Corticosteroids at 1 mg/kg body weight for at least one month, low-dose bevacizumab (5 mg/kg body weight every three weeks) and surgery are generally recommended.