According to the Pathology suggests that obstructive ventilation dysfunction, decreased elasticity of end lung tissues, decreased alpha1-antitrypsin levels, and smoking are the main causes of emphysema. 1. Obstructive Ventilation Dysfunction: Emphysema is often secondary to other obstructive lung diseases, and chronic bronchitis is the most common. Because the onset of chronic bronchitis leads to narrowing of the bronchial tubes, the outflow of gases is impeded, which leads to an increasing amount of residual gas in the terminal lung tissues, resulting in the formation and onset of emphysema. 2. Decreased elasticity of terminal lung tissues: elastic fibers in terminal lung tissues, if damaged in large quantities, will lead to weakening of the elastic retraction force of the tissues, and thus may also cause emphysema. 3. Decreased level of α1-antitrypsin: α1-antitrypsin itself is widely present in tissues and body fluids, but when inflammation occurs, α1-antitrypsin becomes inactive, leading to the destruction of lung tissues, which may also cause emphysema. 4. Smoking: Smoking can also lead to the destruction of the lung tissue structure and promote the formation of emphysema. In addition, emphysema is closely related to atmospheric pollution, small airway pollution and pneumoconiosis, while long-term severe emphysema may cause chronic respiratory failure, acute lung infections, chronic pulmonary heart disease and other complications. Therefore, individuals should understand the causes of emphysema and actively do a good job of preventing and treating the disease.