Abstract: Modern acoustics can measure and study sound waves and the related acoustic phenomena quantitatively. Especially, with the development of the latest generation of electronic stethoscopes in recent years, breath sounds are more easily and accurately obtained. In this study, breath sounds in 52 patients with chronic obstructive pulmonary disease(COPD) and 36 healthy controls are collected through pulmonary function tests. It is found that there are significant differences in inspiration-to-expiration ratio and breathing frequency between COPD patients and healthy people (P=0.002) and in the energy ratio between the inspiratory and expiratory phases in the 50~200 Hz frequency band (P=0.035). Breath sound spectrum analysis can objectively quantify the difference in lung ventilation function between COPD patients and healthy people, which, as a new sensitive clinical detection method, can be used as a criterion for doctors to diagnose whether an individual suffers from airway obstruction.