The micro-bubble jet aerator is a novel aerator based on the new mechanism of micro-bubble, which has the extensive applications in the waste-water treatment.The performance of the new aerator is analyzed by the experimental measurement. Results show that the standard oxygen transfer coefficients (K Las) increase from 0.052 L/min to 0.338 L/min, and the theoretical power efficiency (EP) increases from 0.659 kg/kW?h to 4.284 kg/kW?h, when the aerator airflow rate increases from 0.2 m3/h to 2.0 m3/h. Compared with other type aerators, both KLas and EP are improved obviously in the present aerator. Furthermore, the micro-bubble jet aerator is also applied to a real waste-water treatment, and it is verified that there is a high COD Cr removal rate of 76.6% in the effluent water.