In clinical work, we often encounter some patients with bronchiectasis who have been mistakenly thought that they have “bronchitis” before going to the hospital. Bronchiectasis is a common chronic bronchial septic disease, mostly secondary to respiratory infections and bronchial obstruction, especially bronchopneumonia after measles and whooping cough in children and young adults, which results in lumen expansion and deformation due to the destruction of the bronchial walls. The main pathogenic factors are infection of the broncho-pulmonary tissue and bronchial obstruction. Infection causes congestion and edema of the mucous membrane of the lumen, making the lumen narrow, and secretions tend to obstruct the lumen, leading to poor drainage and aggravating the infection; poor drainage of bronchial obstruction induces pulmonary infection, which interacts with each other to promote the occurrence and development of bronchiectasis. Most patients with bronchiectasis have a history of measles, whooping cough or bronchopneumonia that persists in childhood, and later they often have recurrent infections of the respiratory tract. Their typical symptoms are chronic cough with large amounts of pus sputum and recurrent hemoptysis. Therefore, when you have the above three manifestations, do not keep thinking that you have the same old “bronchitis”, but most likely “bronchiectasis”. The treatment for these two is different and you should go to a specialist as soon as possible. The main causes of bronchiectasis are infection and obstruction, which are mutually beneficial. Initially, bronchitis is caused by infection, resulting in bronchial mucosa edema, congestion, increased secretion, enlarged peribronchial lymph nodes with inflammation, and sputum not easily discharged, which aggravates the infection. Repeated infections cause destruction of bronchial wall, narrowing of bronchial scar, easy obstruction of bronchus and become the main factor of bronchial dilatation, and gradually columnar or cystic enlargement of bronchus, which further becomes a “bag” where infected secretions “hide dirt”, and also It becomes a breeding ground for bacterial colonization. On this basis, patients with bronchiectasis are more prone to lung infections than normal people, and infections can occur whenever there is a cold, cold, etc. The infection can even spread from one lung lobe to two or more lung lobes, eventually leading to extensive bronchiectasis in multiple lobes of the lungs bilaterally. In addition, a few patients with congenital defects in the development of bronchial cartilage support tissue are more prone to infection and bronchial dilatation.