Diagnosis: It is mainly determined by a comprehensive analysis based on the history of smoking and other high-risk factors, clinical symptoms, physical signs and pulmonary function tests. Incomplete reversible airflow limitation is a necessary condition for COPD diagnosis. Incomplete reversible airflow limitation can be determined by FEV1/FVC < 70% and fev1 < 80% of the expected values after inhalation of bronchodilators. A small number of patients with no cough or sputum, but with FEV1/FVC <70% and fev1 ≥80% of the expected value on pulmonary function tests, can be diagnosed with copd after excluding other diseases. Specific treatment measures: (a) Stable treatment 1. Educate and persuade patients to quit smoking; those who are caused by occupational or environmental dust or irritant gases should be removed from the polluted environment. 2.Bronchodilators include short-term on-demand application to temporarily relieve symptoms, and long-term regular application to reduce symptoms. (1) β2 adrenergic agonists: mainly salbutamol aerosol, 100-200μg (1-2 sprays) each time, quantitative inhalation, the effect lasts 4-5 hours, not more than 8-12 sprays every 24 hours. Terbutaline aerosol also has the same effect. It can relieve the symptoms, and there are still salmeterol, formoterol and other long-acting β2 adrenergic agonists, which only need to be inhaled twice a day. (2) Anticholinergic drugs: are commonly used in COPD, the main variety is ipratropium bromide aerosol, quantitative inhalation, the onset of action is slower than salbutamol, lasting 6-8 hours, each time 4o an 80 mix g, 3-4 times a day. Long-acting anticholinergic drugs include tiotropium bromide, which acts selectively on M1 and M3 receptors, 18μg per inhalation, once a day. (3) Theophylline: theophylline extended-release or controlled-release tablets, 0.2g, once every 12 hours; aminophylline, 0.1g, 3 times a day. 3.Expectorant drugs can be applied to those who cannot easily cough up sputum. Commonly used drugs are 30mg of Ambroxol hydrochloride, 3 times a day, 0,2g of N-Ethyl phthalate cysteine, 3 times a day, or 0,5g of carboxymethylstilbestrol, 3 times a day. Dilute mucin 0,5g, 3 times a day. 4.Glucocorticoids For severe and very severe patients (grade III and IV) with recurrent exacerbations, some studies have shown that long-term inhalation of glucocorticoids combined with long-acting β2-adrenoceptor agonists can increase exercise tolerance, reduce the frequency of acute exacerbations, improve quality of life, and even improve pulmonary function in some patients. Currently, the commonly used formulations are salmeterol plus fluticasone, formoterol plus budesonide. 5.Long-term home oxygen therapy can improve the quality of life and survival rate for those with chronic respiratory failure in COPD. It can have beneficial effects on hemodynamics, exercise capacity, pulmonary physiology and mental status. LTOT indications: ①PaO2 ≤ 55mmHg or SaO2 ≤ 88%, with or without hypercapnia. ②PaO2 55-60mmHg, or SaO2<89% with pulmonary hypertension, heart failure edema or erythrocytosis (hematocrit >0, 55). Oxygen is usually administered by nasal cannula with oxygen flow rate of 1, 0-2, OL/min and oxygen duration of 10-15 h/d. The aim is to achieve PaO2 ≥ 60 mmHg and/or to raise SaO2 to 90% in the patient’s resting state. (B) Treatment of acute exacerbation 1. Determine the cause of acute exacerbation and the severity of the disease. The most common cause of acute exacerbation is bacterial or viral infection. 2.Decide on outpatient or inpatient treatment according to the severity of the disease. 3.Bronchodilators The drugs are the same as in the stable phase. Those with severe wheezing symptoms can be treated with larger doses of nebulized inhalation, such as 500μg of salbutamol or 500μg of ipratropium bromide, or 1000μg of salbutamol plus 250-500μg of ipratropium bromide, which can be given to patients through a small nebulizer to relieve symptoms. 4.Low flow oxygenation Those who have hypoxemia can be oxygenated by nasal catheter or oxygenated by Venturi mask. When nasal catheter oxygen is administered, the oxygen concentration of inhalation is related to the oxygen flow rate, and the estimation formula is inhalation oxygen concentration (%) = 21+4×oxygen flow rate (L/min). The general inhalation oxygen concentration is 28%-30%, and the high inhalation oxygen concentration should be avoided to cause carbon dioxide retention. 5.Antibiotics When the patient’s dyspnea worsens, cough with increased sputum volume and purulent sputum, antibiotics should be actively selected for treatment according to the type of common pathogens and drug sensitivity of the patient’s location. For example, β-lactam/β-lactamase inhibitors; second-generation cephalosporins, macrolides or quinolones should be given. For example, amoxicillin/clavulanic acid, cefazoxime 0,25g 3 times a day, cefuroxime 0,5g twice a day, levofloxacin 0,4g once a day, moxifloxacin or gatifloxacin 0,4g once a day can be used in outpatients; in more serious cases, third generation cephalosporins such as ceftriaxone sodium 2,0g in saline can be used for intravenous infusion once a day. Inpatients when according to the severity of the disease and the expected pathogenic bacteria more aggressive antibiotics, generally more intravenous drip administration. If the exact pathogen is found, antibiotics are selected according to the drug sensitivity results. 6.Glucocorticoids For patients with acute exacerbation requiring hospitalization, consider giving oral prednisolone 30-40mg/d, or intravenous methylprednisolone 40mg-80mg once daily. Continuous for 5-7 days. 7.Expectorant bromhexine 8-16mg 3 times a day; Ambroxol hydrochloride 3Omg 3 times a day as appropriate.