Chronic obstructive pulmonary disease mainly has the following characteristics: 1. Chronic cough: For patients with chronic obstructive pulmonary disease, chronic cough is a common symptom in the early stage, mainly manifested as morning cough, which may be accompanied by nocturnal paroxysms and sputum discharge. Patients will develop to the end stage with obvious airflow limitation and dyspnea, while the symptoms of coughing are relatively reduced; 2. Coughing sputum: patients with COPD can cough up white mucous sputum or foamy sputum, and when the condition is aggravated or acute aggravation occurs, patients will have more sputum or change in sputum properties, from mucous sputum to purulent sputum; 3. The most common symptom of COPD is shortness of breath, and patients have dyspnea after physical work in the early stage. With the gradual aggravation of the disease to the end stage of the disease, patients will feel difficulty in breathing after physical activities or brushing teeth or washing face, and in serious cases, dyspnea may occur even in the resting state.