Pneumothorax, with signs of gas accumulation in the chest, elevation of the affected side of the chest, reduced respiratory movement and fibrillation, excessive echo or drum sound on percussion, and reduced or absent breath sounds on auscultation, is commonly referred to as pneumothorax, which is a state of gas accumulation caused by gas entering the pleural cavity. It is usually divided into three major categories: spontaneous pneumothorax, traumatic pneumothorax and artificial pneumothorax. Spontaneous pneumothorax is caused by the rupture of lung tissue and dirty pleura due to lung disease, or by the rupture of tiny vesicles and pulmonary blisters near the lung surface, and the entry of air from the lungs and bronchi into the pleural cavity. Spontaneous pneumothorax sometimes resembles other heart and lung diseases and should be differentiated. 1.Bronchial asthma and obstructive emphysema have shortness of breath and dyspnea, and the signs are similar to spontaneous pneumothorax, but dyspnea in emphysema is slowly aggravated for a long time, and patients with bronchial asthma have a history of recurrent asthma attacks for many years. When asthma and emphysema patients have sudden worsening of dyspnea and chest pain, the possibility of complicated pneumothorax should be considered, and X-ray examination can make the distinction. 2, acute myocardial infarction Patients also have acute onset of chest pain, chest tightness, even dyspnea, shock and other clinical manifestations, but often have a history of hypertension, atherosclerosis, coronary artery disease. Physical signs, electrocardiogram and X-ray chest x-ray can help diagnose. 3.Pulmonary embolism has clinical manifestations similar to spontaneous pneumothorax such as chest pain, dyspnea and cyanosis, but the patient often has hemoptysis and low fever, and often has a history of lower limb or pelvic embolic phlebitis, fracture, severe heart disease, atrial fibrillation, or occurs in elderly patients who are bedridden for a long time. Physical examination and X-ray examination can help to identify. 4. Pulmonary herpes Pulmonary herpes located in the peripheral parts of the lung are sometimes mistaken for pneumothorax on X-ray. Pulmonary blisters can be formed due to congenital development, or they can form tension cysts or giant cavities due to obstruction of endobronchial valves, with slow onset and non-severe shortness of breath. The pulmonary blister expands peripherally, pressing the lung toward the apical region of the lung, the angle of the rib diaphragm, and the angle of the heart diaphragm, while the pneumothorax presents as a translucent band on the outside of the chest, in which no lung lines are visible. The pressure within the pulmonary blister is similar to atmospheric pressure, and there is no significant change in the volume of the blister after aspiration.