In the process of sewage treatment, the sewage usually needs to be aerated, so the oxygenation efficiency is an important indicator for the aerator. The general oxygenation technique is to inject large amount of natural air into the aeration tank over long time, which has lower efficiency and leads to dramatic waste of energy. Based on the gas-liquid fusion mass transfer model and combined the oxygen enrichment mechanism by magnetization of the gas into the aerator, a novel method to improve the efficiency of wastewater oxygenation is proposed. This method is based on the fact that oxygen and nitrogen exhibit completely different magnetic characteristics in gradient magnetic fields, and then the special shaped permanent magnets can be used to build a target gradient magnetic field to increase the oxygen content as the gas is injected into the sewage by the aerator, which reaches the oxygenation enhancement effect. Through theoretical analysis and experiments, it is concluded that the efficiency of sewage oxygenation treatment is dramatically improved with the permanent magnet oxygen enrichment technique.