The airways and intestines of the human body are colonized with a large number of microorgan⁃isms. In recent years，studies have found that changes in the airways and intestinal flora affect the frequency andseverity of acute COPD attacks，and the metabolites of the intestinal flora is involved in the regulation of lunginflammation and immune response in patients with COPD，via the“gut⁃lung axis”. This article aims to review thecomposition and diversity of the lung and gut microbiome of COPD patients in different stages of the disease1course，as well as the effects of smoking and treatment methods on them，in order to provide a new direction forthe treatment of COPD.