Chronic obstructive pulmonary disease (COPD), a chronic disease with complicated pathogenesis, is the end-result of complex, cumulative and dynamic Gene-Environment-Time interactions over the lifetime that can damage the lung and/or alter normal development. COPD is a leading cause of morbidity and mortality worldwide, accounting for heavy economic and social burden which are continuously increasing. In order to provide clinical references for its diagnosis and treatment, this article reviewed the key issues of COPD, including definition, diagnosis, and therapy, which are based on the update of 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD)