The main causes of shortness of breath in lung cancer patients in late stage are as follows: 1. The common cause is the compression of trachea and bronchus, which leads to airway blockage and difficulty in breathing. If the lesion is large and the general state of the patient allows, radiotherapy can be considered to relieve the compression symptoms of the lesion. If the lesion is wide in scope and has no therapeutic value, there is no special treatment in general, and drugs to calm asthma and resolve phlegm can be given to relieve shortness of breath.2. Lung cancer invades the alveolar tissue in the lung, resulting in alveoli unable to complete normal ventilation and gas exchange function, causing shortness of breath, which can only be controlled by effective chemotherapy. If the patient has no chance of chemotherapy, he can only give corresponding anti-infection, give small dose of hormone to calm asthma and carry out symptomatic treatment to relieve shortness of breath.3. Lung cancer invades the pleura and the invasion of pleura leads to the production of pleural fluid, which will cause shortness of breath and can be relieved by pumping pleural fluid. If the patient’s pathological type is clear and the systemic state allows, intrapleural instillation of chemotherapy drugs can also be given to control pleural fluid after pleural fluid extraction. If none of the other conditions above is the cause of shortness of breath, some patients with shortness of breath may also be due to long-term chronic consumption of tumor, resulting in anemia. Regardless of the causes of shortness of breath in advanced lung cancer patients, there is no very good cure for it, and all treatments can only temporarily relieve the symptoms.