Lung cancer, especially non-small cell lung cancer, is very willing to develop brain metastasis, and brain metastasis from lung cancer is the first among all cancers in the body. It is usually considered that brain metastasis of lung cancer is the advanced stage of lung cancer. For brain metastasis of lung cancer, most patients are not considered for craniotomy. However, with the continuous progress of targeted drug treatment for lung cancer, the 5-year survival rate of lung cancer is getting higher and higher. Targeted drugs have better control on primary foci but not on brain metastases, so surgical treatment of brain metastases becomes more and more important. For single metastases of large size, if the primary foci have been resected, the patient has good general conditions and no metastases from other parts have been detected, early surgery should be performed. For patients with intracranial metastases and primary lung cancer found at the same time, the primary foci should generally be removed first, followed by the metastases, but when the patient has obvious intracranial symptoms, the intracranial metastases can also be removed first, followed by the primary foci; because most of the brain metastases are located in the superficial parts of brain tissue, sometimes craniotomy may be safer than open surgery. Because after brain metastasis occurs, usually the metastatic cancer progresses faster in the brain than the primary cancer in the lung, for patients whose primary lesions cannot be removed, only intracranial metastatic cancer can be removed to relieve symptoms and prolong life.