As coking wastewater has characteristics of high toxicity, high phenol cyanide index, high ammonia nitrogen concentration, large fluctuation of water quality, poor biodegradability and so on, A2O-Fenton process was used for its treatment. The results of engineering operation showed that, the mass concentration of CODCr decreased from 3 500- 5 000 mg/L to below 150 mg/L, the mass concentration of ammonia nitrogen decreased from 200- 350 mg/L to below 5 mg/L, the removal rates reached 95% and 97% respectively...