A method for efficiently degrading COD in cold-rolled concentrated oil inorganic ultrafiltration effluent comprises the following steps: the concentrated oil inorganic ultrafiltration effluent enters an oxidation tower from the bottom of a high-efficiency COD oxidation tower through a first-stage lifting pump. Ozone generated by an ozone generator also enters the oxidation tower from the bottom of the COD oxidation tower, and the actual ozone concentration of the oxidation tower is 95 g/m3, and the flow rate of the ultrafiltration effluent in the high-efficiency COD oxidation tower is 25-35 m/h. A COD degradation catalyst is placed inside the high-efficiency COD oxidation tower. The water quality PH of the cold-rolled concentrated oil inorganic ultrafiltration effluent is 6-9, and the COD is 210-360 mg/L and the concentration of suspended matter is 35-71 mg/L. By adopting the processing system disclosed by the invention, the production and treatment cost is low, and the method is an environment-friendly steel wastewater green and environment-friendly treatment process.