Pulmonary function tests are one of the necessary tests for respiratory diseases. Their purpose is to understand the physiological status of the respiratory system, to clarify the mechanism and type of pulmonary dysfunction, to determine the degree of lesion damage, to estimate the functional reserve of the lungs and to provide reference for medical treatment. Patients with asthma require ventilation function, bronchodilatation test or/and excitation test depending on their condition. Pulmonary function tests are necessary to diagnose asthma. Pulmonary function tests are not invasive or invasive and are generally not painful for the patient. A complete set of pulmonary function tests can be completed by the patient breathing at various rhythms and depths as requested by the physician.