There is no self-test for lung function, you need to go to a regular hospital and be evaluated by a specialized doctor and have a lung function test conducted under his/her guidance. There are various kinds of pulmonary function tests, with different indicators and different testing methods. For example, when checking pulmonary ventilation function and determining lung volume, it is necessary to calibrate the spirometer first, and then the examinee is instructed to take a seated position, clip the nose clip and connect the mouthpiece with the spirometer, and determine the lung volume after 5 times of calm breathing. If you check the pulmonary ventilation function and determine the exertion lung volume, you need to ask the examinee to sit down, connect with the spirometer and do the maximum inhalation to the total lung volume, then hold the breath for 1 second and exhale to the residual air volume with the maximum force and the fastest speed, and exhale quickly, continuously and uniformly, and then repeat for 2 times. The above only lists some of the lung function test items, the specific testing method is recommended to consult a specialist, under the guidance of the doctor.