Based on the 24-hour monitoring results of quality and quantity of wastewater discharged from the expressway service area, a three-step feeding A/O biological contact oxidation process was employed to treat the expressway service area wastewater which was of high-strength COD and total Kjeldahl nitrogen (TKN). By two stages continuous experiment, the treatment effect of the process to the high-strength COD and TKN wastewater was studied. The experiment results indicated, when the three-step feeding A/O biological contact oxidation process employed to treat the high-strength COD and TKN wastewater, alkalinity was a decisive factor for the treatment effect of the process. When COD, TKN, ammonia nitrogen and total nitrogen (TN) concentrations of the influent were 1030mg/L, 212mg/L, 153mg/L and 213mg/L respectively, and HRT was 36hours, the removal efficiencies of the process to COD, TKN, ammonia nitrogen and total nitrogen were higher than 95%, 98%, 98% and 80% respectively. The effluent quality was superior to the first discharge standard of integrated wastewater discharge standard (GB8978-1996).