Spirometry is the volume of air exhaled to the best of one’s ability after maximum inspiration, and includes three components: tidal volume, compensatory inspiratory volume and compensatory expiratory volume. The greater the lung volume, the greater the ability to inhale oxygen and expel exhaust gases, and the greater the body’s ability to supply oxygen. The spirometer is usually used to measure the size of spirometry. When blowing, the airflow must not be interrupted, once interrupted, the instrument will automatically count as the end of a measurement, blowing, the mouthpiece should be close to the face, do not make the blowing gas through the gap between the mouthpiece and the face overflow, otherwise the measurement results will be affected, the measurement of the end of the mouthpiece should be put into a barrel or box sterilization.