The length of time for breast cancer to metastasize to the lung also varies depending on the individual, the patient’s immunohistochemistry, and genetic analysis. Most early stage patients with breast cancer take 3-5 years to develop lung metastasis, while advanced stage breast cancer patients usually develop lung metastasis in six months. Early stage breast cancer patients are mainly treated by surgery, and if lung metastases appear, they are mainly treated by chemotherapy, immunotherapy, targeted therapy, and also combined with Chinese herbal medicine. Chinese herbal medicine is mainly used to benefit qi and improve immunity, such as Astragalus, Radix et Rhizoma, Epimedium, Ganoderma and Salvia. Chemotherapy for patients with advanced breast cancer lung metastasis, first-line chemotherapy with epirubicin combined with paclitaxel and cyclophosphamide, such as gemcitabine, capecitabine combined with anti-vascular inhibitors or targeted therapy, and now immunotherapy can also be used.