The invention discloses a molecular sieve oxygenerator, which comprises a shell, an atomization gas source outlet, an air intake filter, and a humidification bottle. Specifically, the humidification bottle is positioned at the middle part of the shell's outer surface, the atomization gas source outlet is positioned on a side of the humidification bottle, and the air intake filter is located at the lower part of the shell. The humidification bottle consists of a bottle body and a bottle cap that are in threaded connection, and a sealing strip with double-layer rubber is disposed at the periphery of the joint of the bottle body and the bottle cap. With a simple and reasonable structure, the molecular sieve oxygenator provided by the invention adopts an advanced gas separation technology to extract oxygen from the air directly, and oxygen is ready-to-use after being prepared, and is fresh and natural. The molecular sieve oxygenerator has no risk of high pressure and explosiveness, etc. And the contained humidification bottle has good sealing performance, and outleakage of oxygen from the humidification bottle is effectively prevented, thereby enabling sufficient oxygen supply.