As VVVF (Variable Voltage Variable Frequency) used in the automatic control of aeration brush can realize the best matching of oxygen demand and oxygen supply through changing the revolving velocity of aeration brush in an oxidation ditch, as a result, the energy consuming is reduced in the greatest extent with guaranteed effluent water quality. At the same time, the feasibility and necessity of VVVF in the automatic control of aeration brush is proved. In this paper all ways of the control of aeration brush are introduced in the factual use. The energy saving can be achieved through the control of changing frequency in the automatic control ways of computer system.