OC5B Oxygen Concentrator consisted of air compressor, adsorption tower of molecular sieve, sensor and flowrate controller. With the molecular sieve to be absorbent, the machine adopts PSA(pressure swing absorbers ) method to directly concentrate medical oxygen with high concentration from the air. It is small and mobile. The machine takes the advantages of small in volume, light in weight, convenient in moving (as it has turning truckle), stable in performance, high in safety, easy in operating, low in noise, safe in working, which complies with requirements of medical device. The machine has a wide application, including clinic, hospital, oxygen bar, plateau outpost, gym center, etc.