The anesthesia machine sends anesthetics into the patient's alveoli through a mechanical circuit to form a partial pressure of anesthetic gas. After diffusing into the blood, it directly inhibits the central nervous system, thereby producing the effect of general anesthesia. The anesthesia machine is a semi-open anesthesia device. It is mainly composed of anesthesia evaporation tank, flowmeter, folding bellows ventilator, respiratory circuit (including suction, exhalation one-way valve and manual airbag), bellows road and other components.