The sound of whistling in the airways during exhalation is common in clinical practice in specific diseases of the respiratory system, such as bronchial asthma, wheezing bronchitis, and wheezing bronchopneumonia. Due to exposure to cold air, sulfur dioxide, pollen or irritating odors, such as ammonia, these suspected allergens are inhaled into the airways, stimulating congestion, edema, and exudation of inflammatory substances from the airways, accompanied by contraction and spasm of the smooth muscles of the airways. At this time, the lumen of the airway becomes narrow, and the secretion of the airway wall and the impact of the narrowed airway will emit a whistling sound when inhaling, and at this time, a CT of both lungs can be taken to check the lung function and clarify the diagnosis.