Indications for mask oxygenation, including ordinary mask, oxygen storage mask and venturi mask, ordinary mask has no one-way skin flap and oxygen storage bag, oxygen input port is located at the bottom, so the oxygen flow rate of ordinary mask is 5-8l/min, oxygen concentration is 40%-60%, suitable for patients with type I respiratory failure and respiratory distress syndrome where hypoxemia is more severe. The oxygen storage mask has an oxygen storage bag, and there is a one-way valve between the mask and the oxygen storage bag, for the mask gas only in and out, and there is a single skin flap on the mask, for the mask gas only out and not in, the oxygen flow rate is about 10-15l per minute, and the oxygen concentration is up to 90% or more, suitable for patients with severe hypoxemia, unstable respiratory status type I respiratory failure and respiratory distress syndrome. Venturi mask principle is that oxygen passes through a narrow orifice to produce negative pressure, carrying a certain amount of air from the open side holes with the size of the side holes of the mask mask, changing the ratio of air to oxygen, so it can adjust the oxygen concentration as needed. Venturi mask is suitable for patients who need to provide fine oxygen concentration, hypoxemia with hypercapnia, such as type II respiratory failure caused by chronic obstructive pulmonary disease, etc.