Coke oven waste water is respectively pretreated by blast furnace sludge method and blast furnace sludge plus iron scrap method, the effects of pH and the quantity of materials and treatment time on the removal efficiency of COD are analyzed. The results indicate that blast furnace sludge plus iron scrap method is superior to blast furnace sludge method .The treatment time and pH can greatly affect on the removal efficiency of COD using blast furnace sludge plus iron scrap method. The treatment time after 30 minutes and pH have no remarkable effects the removal efficiency of COD using blast furnace sludge method. The removal efficiency of COD increases with the increase of blast furnace sludge and iron scrap, but the increase rate decreases gradually.