The diagnosis of pneumothorax is divided into the following aspects: 1. Symptoms: The common symptoms of pneumothorax are sudden chest pain, chest tightness, shortness of breath, and difficulty in breathing. In addition to these, patients with severe pneumothorax may even show cyanosis and syncope; 2. Signs: the thorax is relatively full, while the doctor percusses with a drum sound. During auscultation, the breath sounds on the affected side will decrease; 3. The most commonly used is X-ray or CT examination. Especially CT, the popularity of which has been very high in recent years. CT can not only know the presence or absence of pneumothorax, but also the extent of pneumothorax, the location of air accumulation, and even the presence or absence of tension and mediastinal deviation.