Inclusion Criteria:  Age between 40 and 80 (including 40 and 80) It meets the diagnostic criteria for COPD No language communication barriers, or the family members who know the condition can complete the questionnaire on behalf of the patient, and the data are reliable; Voluntarily agree to participate in this study  Exclusion Criteria:  Older than 80 or younger than 40 Pregnant women Complicating with other lung diseases, such as asthma, pneumonia, bronchiectasis, lung abscess, interstitial lung disease, confirmed and suspected lung cancer of lung shadow, active pulmonary tuberculosis, etc Previous lung surgery Cognitive dysfunction Unable to cooperate with lung function test.