Abstract: The treatment of coking wastewater was researched by ultrasonic wave. The influences of irradiation time, ultrasonic power, initial pH value of coking wastewater, initial concentrations of chemical oxygen demand (COD_Cr) and ammonium (NH₄⁺), and dissolved gas on the removal of COD_Cr and NH₄⁺ were investigated systematically. The ultrasonic treatments of coking wastewater combined with oxidants were comparatively analyzed. The results show that the ultrasonic treatment combined with H₂O₂ or Fenton reagent had a synergetic effect, and then the removal rates of COD_Cr, and NH₄⁺ greatly increase. The order of removal rate is the following:ultrasonic treatment + Fenton 〉 ultrasonic treatment + H₂O₂ 〉 Fenton 〉 ultrasonic treatment 〉 H₂O₂. According to the analysis results of GC-MS, the removal process of COD_Cr and NH₄⁺ was preliminary studied. It is found that the proportions of non-biodegradation organisms, such as naphthalene, anthracene and quinoline, obviously decreased in treated coking wastewater.