Through testing the oxygenation performance of an aerator at different water temperatures, the effects of water temperature on the oxygen mass transfer coefficient was studied. The test water tank was placed in a walk-in thermostatic experimental chamber, an aerator was installed in the test tank filled with tap water, and the total volume of water in the tank remained unchanged during the test. The temperature in the chamber could be adjusted between -40℃ ~ +80℃, controlled via heat balance temperature regulation mode via a programmable touch LCD screen. Through adjusting the temperature of the test chamber, the water temperature was indirectly changed, hereby the oxygenating capacity of the aerator was tested at 20 different water temperatures ranging from 6℃ to 28℃, and the relationship between water temperature and aerating capacity was analyzed. The results showed that under different water temperatures, there was a great difference in the oxygenating capacity, which decreased with the increase of water temperature. When the water temperature rose from 6℃ to 28℃, the oxygenating capacity decreased by 35.5%. The aerating capacity was positively related to the oxygen mass transfer coefficient and saturated dissolved oxygen, but it varies obviously much at different water temperatures, for which the value of temperature correction coefficient might be one important reason. The study showed that the value of temperature correction coefficient θ should change with the change of water temperature. When the temperature was above 20℃, the value of θ dropped with the increase of temperature. When below 20℃, the θ value had no obvious linear relationship with the water temperature, and instead of a constant value of 1.024, it fluctuated between 1.00 and 1.01.