Phase hybrid biological reactor (HBR) was used in treating coke wastewater by adding submerging fiber-bail fillers in suspended growth activated sludge.The optimum operation parameters for the highest performance were determined.It was found that the hybrid biological reactor worked well for the coke wastewater treatment in terms of Chemical Oxygen Demand (COD), NH4+-N and other refractory organic compounds removal efficiencies.Compared with conventional activated sludge system, the removal rate of COD and NH4+-N and the nitrating rate were higher and more stable in the hybrid biological reactor.COD of effluent was less than 75 mg/L and the removal rate of COD and NH4+-N could be up to 95.0% and 92.5% when COD of influent and NH4+-N were less than 700 mg/L and 300 mg/L, respectively.In this way, the quality of effluent concentration could reach the first class of integrated wastewater discharge standard (GB8978-1996) (COD≤100mg/L).