Oxygen is used to correct the defects caused by various reasons, to maintain the vital activities of the body and to accelerate the body’s metabolism. There are many ways to absorb oxygen, such as nasal catheter, nasal plug method, mask oxygen, etc. Generally, mask oxygen is used in the following cases: First, when the patient has nose disease, no way to breathe through the nose or damage to the nasal mucosa, no way to use nasal catheter oxygen will choose mask oxygen. Secondly, when the oxygen deficiency is serious, the oxygen intake by nasal catheter cannot meet the oxygen demand, and the mask can bring a higher oxygen concentration. Thirdly, when children cannot cooperate with nasal catheter oxygenation, they use mask oxygenation. Fourth, when the concentration of carbon dioxide in the body is relatively low, using a mask to inhale oxygen can increase the inhalation of carbon dioxide.