Abstract: DO (dissolved oxygen) at different depth and distance from a working spray-type surface aerator in high-yielding fish ponds was measured. It was indicated that in the case of oxygen insufficiency, DO near the aerator was slightly higher, and the aerator played an important role in supplying oxygen and avoiding crisis for fish; in the case of oxygen over-saturation, DO near the aerator was lower because of diffusion of oxygen from water to air, and the aerator played a role of mixing instead of aeration which caused the stratification of water temperature and DO be broken so that the water quality might be improved.The oxygen diffusion through the interface of air-water was studied. By analyzing the forces for water differ-ential round a working aerator, a theoretical expression of its power consumption,, was presented.Some new methods including partial aeration and increasing air flow were suggested to improve the aeration efficiency. A few new viewpoints and references for further studies and application on spray-type surface aerator were given.