It is the social responsibility of power grid enterprises to actively implement the national environmental protection policy. The classification of substation effluent, the present situation of oil-water treatment in substation, the environmental risk of substation effluent, the treatment methods of production effluent and domestic effluent are described in detail. Biological contact oxidation method is usually used to treat domestic sewage of substation, and the treatment measure of production wastewater is “High-efficiency adsorption + electric oxidation” integrated accident oil pool, and the oil-water separation device is installed inside the accident oil pool, when the oily wastewater flows into the accident oil pit, the oil-water separation is carried out by the oil-water separation facilities, and the waste water is discharged after being treated by the oil-water separation device.