Inclusion Criteria:  Clinical diagnosis of COPD Tobacco use: current or former smokers with a continuous smoking history of more than 1 year. Subjects are willing and able to complete the follow-up according to the plan. Subjects can cooperate to complete relevant examination items. Compliance: Subjects must be willing to return to the hospital and complete all visits and evaluations according to the protocol.  Exclusion Criteria:  Having a significant disease or condition other than COPD that, in the Investigator's judgment, would put the subject at risk for participating in the study or affect the study outcome and the subject's ability to participate in the study. Women who are pregnant or breastfeeding or who plan to become pregnant during the study period.  Digestive system: ① patients with known gastrointestinal organic diseases.  ② Complicated with intestinal double infection, such as Clostridium difficile infection, EHEC, Salmonella, Shigella, Campylobacter, plague and cytomegalovirus;  ③ patients with various acute infections, tumors, severe arrhythmias, mental disorders, drug or alcohol addiction; (4) pregnant or lactating women; (5) Use of antibiotics or probiotics within the last 4 weeks; (6) There are taboo witnesses for this study; (7) Clinical investigators who were conducting other related COPD studies at the time of enrollment or within 3 months before enrollment;  Complicated with serious primary diseases of heart, liver, kidney, hematopoietic system and other important organs or systems. Patients with lower back, chest and abdomen injuries or after surgery. People with mental disorder or cognitive impairment. Non-compliance: Subjects did not follow the study procedures, including non-compliance to complete the journal. Informed consent validity is in doubt: Subjects with a history of psychosis, mental retardation, poor motivation, substance abuse (including drugs and alcohol), or other medical conditions that limit the effectiveness of informed consent in this study. Obesity (BMI≥28) Hyperlipidemia (1.5 times the upper limit of normal value of plasma total cholesterol > or 1.5 times the upper limit of normal value of triglyceride BBB>; Confirmed diabetic patients; Diagnosed cancer patients; Have used any antibiotics or antibiotics in the last 2 weeks.