Usually elderly men who usually smoke suffer from chronic bronchitis. Chronic bronchitis continues to develop and will develop into chronic obstructive pulmonary disease, at which time a chest CT will reveal emphysema. Emphysema is mainly caused by a decrease in the texture of both lungs, the alveolar inflation sign is more obvious, the patient inhales more gas but exhales less gas, the alveolar elasticity is reduced, most of the gas accumulates in the alveoli and cannot be exhaled. At this time, the patient’s breath sounds are diminished on auscultation, and the thorax is barrel-shaped, the bilateral rib space is widened, and the percussion is hyperclear. If the emphysema develops further, such as the patient’s wheezing is further aggravated or violent coughing, the alveoli are already less elastic, and if the alveoli rupture and fuse together, they will form alveoli, which will develop further and easily develop into pneumothorax.