Chemotherapy can be started 3-4 weeks after lung cancer surgery. If the recovery after lung cancer surgery is relatively good, chemotherapy can usually be started 3-4 weeks after surgery, and the specific time of chemotherapy needs to be determined under the guidance of doctor according to the patient’s condition and recovery. The starting time of postoperative chemotherapy for lung cancer is usually not more than 8 weeks. Lung cancer is generally divided into non-small cell lung cancer and small cell lung cancer. Small cell lung cancer is generally not treated by surgery and is usually given radiotherapy or chemotherapy; non-small cell lung cancer is given surgery or radiotherapy according to the situation. Non-small cell lung cancer patients are usually given 4-6 weeks of postoperative adjuvant chemotherapy after surgery. Stage IA lung cancer patients can be observed regularly after surgery, while stage IB patients can be treated with targeted therapy or postoperative adjuvant chemotherapy according to the presence or absence of high-risk factors and the patients’ wishes. stage II lung cancer patients need to be treated with postoperative adjuvant chemotherapy and other treatments after surgery. Chemotherapy should be carried out under the guidance of oncologist after lung cancer surgery.