Abstract: In order to study how water with low dissolved oxygen changes over time after passing liquid whistle ultrasonic aeration equipment, this study conducted static tests of the water after aeration and monitored the changing trends of the dissolved oxygen content in water body over time. In this study, six groups of test were applied and among them, two variables, reed or not and change of flow, were set. The results showed that after the aeration of the equipment in the experimental group, which added a reed, the dissolved oxygen content in the water would continue to increase in the first 2 hours and then reached the maximum value. 2 hours later, the dissolved oxygen content would fall sharply and the descending rate slowed down after 6 hours. When 20 hours passed, the dissolved oxygen content in the test water became stable around 7.4mg/L. The control group reached the peak at 2 hours, and the dissolved oxygen content decreased slowly at 2~3 hours. It would keep increasing later and finally achieved stability around 7.15mg/L after 20 hours. We can get a series of scientific and reasonable variation curve of dissolved oxygen content from the tests and could conclude that adding a reed and smaller flow have a positive influence on aeration. Moreover, this study provides important research value for the aerator application in aquiculture, sewage treatment and oxygen aeration irrigation fields.