Abstract: In the wastewater treatment process of stabilization pond, oxygen plays an important role in oxygenic decomposition from organism. The sourecs of oxygen in stabilization pond are alga photosynthesis and air re aeration. Light and non light contrast experiment, air re aeration experiment and data analysis are studies in this paper. Oxygen release amount of alga photosynthesis and air re aeration is calculated, and the proportion of oxygen supply with the removal parts of organism in stabilization pond is also calculated. The conclusion is that air re aeration is the main oxygen supplier in stabilization pond.