Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease characterized by airflow limitation, causing COPD mainly as a result of the combined effect of genetics and environment. The causes of this disease are as follows: 1. Genes: COPD is a polygenic disease. 2. Environmental factors: (1) Exposure to harmful substances, such as smoking, occupational exposure to dust and chemicals, indoor and outdoor air pollution, etc. (2) Lung growth and development, any factors that can affect lung growth have the potential to increase the risk of COPD in individuals. (3) Infection, infection with bacteria or viruses, plays a role in the occurrence and progression of the disease, and bacterial colonization is associated with airway inflammation and plays an important role in acute exacerbations. (4) Socioeconomic status, the risk of developing the disease is negatively associated with socioeconomic status. The etiology of COPD can be used as primary prevention of COPD, such as smoking, indoor air pollution, and poorly controlled asthma. Smoking cessation is the most important intervention for COPD patients who smoke. Other exposures including dust and smoke should be avoided as much as possible.