When brain metastasis occurs in lung cancer, we must first determine the type of lung cancer, whether it is small cell lung cancer or non-small cell lung cancer. If it is small cell lung cancer presenting with brain metastasis, there is no particular targeted drug available at the moment. However, if it is adenocarcinoma with brain metastasis, we can determine what targeted drug to take according to the EGFR gene mutation. Generally speaking, ERSA, Exatinib and the latest Ocetinib have certain effects on brain metastasis. Therefore, not everyone is suitable to take targeted drugs for lung cancer brain metastasis, if not, it is necessary to cooperate with adjuvant radiotherapy.