In 2014, the number of new lung cancer cases in China was 605,900 and the number of deaths reached 486,600, accounting for 1/4 of the causes of death from malignant tumors, and the lung cancer we often talk about includes the two major categories of non-small cell lung cancer and small cell lung cancer. The reason why lung cancer is malignant is that it likes to wander and settle in other parts of the body (metastasis) from the old nest (primary focus) in the lung. The incidence of brain metastasis is about 20-30% when lung cancer is initially diagnosed, but with the progress of treatment, the patient lives longer and longer, the incidence of brain metastasis can be as high as 50-60% during the whole treatment process, so the prevention and treatment of brain metastasis is urgent. What are the causes related to the occurrence of brain metastasis of lung cancer? Firstly, it is the pathological type: among non-small cell lung cancer, lung adenocarcinoma and small cell lung cancer are the most prone to brain metastasis; secondly, it may be related to certain targeted gene mutations: for example, non-small cell lung cancer with EGFR mutation is reportedly three times more likely to have brain metastasis than patients without mutation, and lung cancer patients with positive ALK fusion gene are also prone to brain metastasis. Prevention is much more important than treatment in the treatment of tumors, because preventive treatment can significantly reduce the mortality and disability of tumors. In small cell lung cancer, prophylactic brain radiotherapy will significantly reduce the occurrence of brain metastasis in later stages, provided that the primary tumor has been well controlled by prior therapies such as chemotherapy and radiotherapy. However, in patients with lung adenocarcinoma, there is no definite treatment to prevent the occurrence of brain metastasis, but in some special populations, such as patients with EGFR mutation, the use of targeted drug Erlotinib (Troche) will reduce the occurrence of late brain metastasis. The main treatment methods for brain metastases from lung cancer are surgery, radiotherapy, and drug therapy (including targeted drugs and chemotherapy). Surgery is mainly used for single tumor or rescue treatment in critical cases. Radiotherapy and pharmacotherapy are the main methods. In the past, once a lung cancer patient developed brain metastasis, it was undoubtedly a death sentence. Because the treatment means is mainly whole brain radiotherapy, which is only palliative treatment with poor effect, and most chemotherapy drugs cannot enter the brain. However, nowadays, with the deepening of basic research on lung cancer, more and more new drugs appear and radiotherapy technology has also made great progress, the treatment effect of lung cancer brain metastasis has been significantly improved. Nowadays, stereotactic radiotherapy technology has been maturely applied in the treatment of brain metastases, and stereotactic radiotherapy technology is commonly known as Gamma knife or X-knife. With today’s technology, it is possible to treat a single tumor, several tumors or even more than ten tumors together, and this radiotherapy technology can achieve the effect of local cure. Therefore, nowadays, the treatment of brain metastasis is more often applied to stereotactic radiotherapy, which has good effect and less damage to brain function, while whole brain radiotherapy is more of remedial treatment. What is the status of drug therapy in brain metastasis? Non-small cell lung cancer has entered the era of targeted therapy, in which 60% of lung adenocarcinoma patients have targeted gene mutations, including EGFR and ALK gene mutations, and these patients are treated with their corresponding targeted drugs. For patients with EGFR mutation combined with brain metastasis, oral treatment with Troche is a good choice. Troche can achieve 60-70% control rate of brain metastasis in these patients, and even some patients can have their brain metastasis disappear completely. For patients with ALK mutations, oral crizotinib (Securitinib) combined with brain radiotherapy can also achieve good results, while second-generation ALK-targeted drugs (cretinoin or Alectinib) have better control rates of brain metastases. Another class of anti-vascular targeted drugs, bevacizumab (Avastin), can improve neurological symptoms caused by brain metastases from lung cancer and has an added effect in combination with targeted drugs or chemotherapy. Among chemotherapy drugs, pemetrexed disodium, which is effective in lung adenocarcinoma, can control brain metastases very well. In small cell lung cancer, the chemotherapeutic agents pegylated glycosides and temozolomide also work well in the brain. Nowadays, the treatment of lung cancer brain metastases is multidisciplinary: targeted drugs combined with chemotherapy; targeted drugs combined with radiotherapy; chemotherapy combined with radiotherapy, and even at a certain stage, the intervention of surgical treatment, which is stronger and more effective. We hope that through multidisciplinary treatment, patients with brain metastases from lung cancer will have better quality of life and longer survival time. Our goal is not only to live long, but also to live well!