The lung tissue is like a sponge, and the alveolar interval is covered with extensive capillary network, which not only inhales oxygen and expels carbon dioxide, but also has filtration function, plus the whole body venous blood must flow through the lungs for air-blood exchange. Therefore, when malignant tumor cells are disseminated by blood, the capillary network in the lungs is the easiest place to reach and form lung metastases by local implantation. Approximately 20-54% of cancer patients will develop lung metastases during their natural course of disease, and the incidence of lung metastases is increasing as tumor patients survive longer. Pulmonary metastases are most commonly seen in patients with tumors of the breast, colon, kidney, uterus, prostate, and oropharynx. Previously considered a contraindication to surgery when a malignant tumor has distant metastases, a series of studies have shown that aggressive surgical treatment of patients with pulmonary metastases who meet the indications can significantly prolong survival and patients may benefit in the long term. For some patients surgical removal of lung metastases may be the best treatment option. Patients with lung metastases from colorectal cancer currently have a 5-year survival rate of 30-50% after surgical resection, which is much higher than patients treated by other methods (less than 10% 5-year survival rate with non-surgical treatment). Surgical intervention improves the long-term survival of patients with pulmonary metastases because: the lung is the most common and initial site of metastasis for many malignancies, and surgical resection can stop their further spread; the lung may also be the only metastatic organ for some malignancies, and aggressive surgical intervention in these patients will achieve good results; some tumors are not sensitive to radiotherapy (e.g., osteosarcoma), and surgery becomes the Some tumors are not sensitive to radiotherapy (e.g., osteosarcoma), so surgery becomes the first choice; numerous studies have reported better surgical outcomes and lower mortality rates for pulmonary metastases. The choice of surgery for pulmonary metastases tends to be conservative, and economic resection is advocated, i.e., to preserve as much normal lung tissue as possible and improve the quality of life of patients after surgery, provided that the metastases can be completely resected. The principles of surgical resection of pulmonary metastases are: the primary tumor is controlled, the metastatic lesions can be completely resected, and extra-pulmonary metastatic lesions (except for potentially completely resectable liver metastases) are excluded. The most important prognostic factors are complete resection of the lesion, the precise location of the tumor, tumor-free survival, and the number of metastases. The surgical requirement is that the lesion must be completely resected, but at the same time as much normal lung tissue needs to be preserved to preserve the patient’s lung function.