Abstract: The COD_(cr) of the effluent from the secondary biological treatment process of coking waste water couldn't meet the standard.In order to resolve the problem,the effects of advanced treatment of coking waste water by ozone catalytic oxidation technology was analyzed through a pilot test.The influence of p H value,reaction time,ozone dosage,and the catalyst on COD_(cr) removal rate were investigated. The optimal operating parameters were determined. After 68 days continuous operation,when the dosage of COD_(cr) ranged from 140 mg / L to200 mg / L,the reaction time were 1. 5 h,the ozone flow velocity were 80 mg /( L · h),the average COD_(cr) removal rate was above 60%which met the Emission Standard of Pollutants for Coking Chemical Industry,China( GB 16171—2012).The operation cost was RMB 1. 30 per cubic meter which accounted for only 25% to 50% of the operation cost of forced coagulation and sedimentation technology.The process was stable and reliable in operation.The specific surface area and pore structure didn't change significantly after and before the use of catalyst.Meanwhile,the catalyst still had activity.