Many patients have incorrect understanding of oxygen therapy. For example, some patients think that long-term oxygen inhalation will be "addiction", or that long-term oxygen inhalation will cause "resistance" like antibiotics, and the effect will become worse and worse in the future. In fact, long-term family oxygen therapy and smoking cessation are two ways to change the natural course of chronic bronchitis. Home oxygen therapy can correct hypoxemia in patients with chronic bronchitis and delay the deterioration of the condition. The curative effect of oxygen therapy is unmatched by all current drugs. It is recommended that all patients with indications receive home oxygen therapy as much as possible. Before long-term home oxygen therapy, perform blood gas analysis to determine whether long-term home oxygen therapy is needed. Oxygen therapy usually involves inhaling oxygen through a nasal cannula at a flow rate of 1.5-2.5 liters/min. The duration of oxygen inhalation should not be less than 15 hours per day, including sleep time. Regularly check lung function, arterial blood gas, blood oxygen saturation, hemoglobin, etc. after oxygen therapy. According to the survey, the main problem that currently exists is that the duration of daily oxygen therapy for patients with chronic bronchitis is relatively short. Most patients in Shanghai (73%) take oxygen for ≤3 hours per day.