Lung infection occurs in lung cancer, which is mostly caused by central type lung cancer. Central type lung cancer occurs near the hilar, which is easy to cause bronchial obstruction and hilar lymph node enlargement, obstructive pneumonia and pulmonary atelectasis. This infection can be relieved in the short term after anti-infection treatment, but due to the special characteristics of the tumor itself, the primary lesion is not removed, and it is easy to recurrently develop lung infection in the same area, which needs to be paid great attention to. Chest enhanced CT and fiberoptic bronchoscopy should be given as early as possible to find out whether there is a microscopic bronchial mass blocking the bronchus. If lung infection occurs in lung cancer it is mostly caused by central lung cancer, peripheral lung cancer is prone to pleural effusion and the chance of lung infection is relatively low. In terms of treatment, once it is clear that lung infection is caused by lung cancer, not only antibiotic treatment should be given, but also aggressive chemotherapy and other treatments should be given to reduce the size of the mass, alleviate the obstruction and relieve the symptoms of lung infection.