Bronchiectasis in the lower lobe of the left lung means abnormal expansion of the bronchi due to structural damage of the bronchial wall. Bronchial dilatation is mainly due to chronic respiratory infections and repeated bronchial inflammation, which leads to the destruction of the structure of the bronchial wall, and this structural destruction is irreversible and difficult to cure. If there are no obvious clinical symptoms, such as no fever, cough, coughing pus sputum, there is no need to worry excessively, but if there are symptoms of high fever, cough, coughing pus sputum, hemoptysis, hospitalization is recommended, and during the hospitalization period, sensitive antibacterial drugs should be taken according to the results of sputum culture to anti-infection, and hemostatic treatment should be given when there is hemoptysis.