The hydrolytic acidification, biological contacting oxidation process has been adopted to treat the wastewater with capacity of 100 m 3/d in the city district. An effluent with BOD<20 mg/L, COD<60 mg/L, SS<20 mg/L, NH 3-N<15 mg/L has been obtained when the inlet BOD,COD, SS and NH 3-N are 86 mg/L, 215 mg/L, 116 mg/L and 28 mg/L, respectively. It meets the national wastewater discharge standard.