Lung function tests are used to understand respiratory function and the condition of the respiratory organs by testing inhaled and exhaled gases. Lung function tests mainly check lung volume function and lung ventilation function. Lung volumetric function includes tidal volume, expiratory volume and inspiratory volume, deep inspiratory volume, lung capacity, functional residual air volume and residual air volume, and total lung volume. Lung ventilation function includes lung ventilation volume, exertion lung volume, maximum expiratory mid-air volume, exertion expiratory volume in one second, and ventilation blood flow ratio. The above tests can help to understand the size of lung capacity, impaired respiratory function, clarify the causes of respiratory diseases, early exclusion of respiratory diseases, assess the severity of the disease, preoperative assessment, provide a basis for the development of disease treatment programs and assess the effect of treatment after treatment. If it is necessary to perform pulmonary function tests, it is recommended to consult with the attending physician at a specialized hospital and follow the doctor’s instructions to exclude contraindications before performing pulmonary function tests.