For primary malignancies of all sites, the lung is the most common site of metastasis. Metastatic lung cancer accounts for 5-10% of lung malignancies. As with the treatment of primary lung cancer, as long as the patient can tolerate open-heart and pneumonectomy, metastatic cancer confined to the lung is advocated for surgical treatment. There are three types of metastatic lung cancer clinically: 1. Multi-nodular type. This type is the most common, mostly located in the middle and lower lobes of both lungs or under the peripheral pleura. They are generally well-defined, spherical or sphere-like, with higher density than surrounding tissues, varying in size, and growing faster. 2.Single nodular type. In the lung field, it shows a single spherical or sphere-like isolated lesion, most of which are less than 5cm in diameter. 3, lymphovascular type. This type is rare, and the metastatic cancer tissues widely invade the lymphatic vessels of the lung. Metastatic lung cancer mostly has no lung symptoms in early stage, but is found during routine physical examination. In case of multiple metastases in both lungs, cough, hemoptysis, chest pain and dyspnea may appear. Therefore, preoperative and postoperative follow-up routine lung X-ray examination is very necessary for patients with malignant tumors. Indications for surgery: 1. The primary lesion has been removed or the disease has been completely controlled. 2. The pathological tissue type of the primary disease is clear. 3, Metastases are confined to the lungs without extra-pulmonary metastases. 4.The lesion can be completely resected. 5, The remaining lung function is normal after complete resection of the lesion. Other factors should be considered during surgery, such as the primary tumor is renal cell carcinoma, fibrosarcoma, etc. should be actively operated, and the 5-year survival rate after resection of metastases is higher. The longer the interval between resection or cure of the primary tumor and the appearance of metastatic lung cancer, the better the treatment effect of metastatic lung cancer. The recurrence of metastatic lung cancer after surgery can still be operated again. Surgical methods: Regardless of stage I or stage II surgery, metastatic lung cancer should be removed completely and normal lung tissues should be preserved to the maximum extent. Unlike the primary lung cancer, it should be resected in a wedge pattern as much as possible. Conventional thoracic surgery incision is more traumatic, and thoracoscopic surgery has unique features. In general, the survival of those with resected metastatic lung cancer is significantly longer than that of those without resection. Overseas reports show that through comprehensive treatment, the 5-year survival rate of resected metastatic lung cancer is 13-50% for renal cell carcinoma, 25-40% for soft tissue sarcoma, and 20-40% for osteoblastoma. Other tumors such as breast cancer and colorectal cancer can also achieve long-term survival.