Abstract: The sewage treatment plant in West Outer Ring of Jinluo Industrial Park was upgraded by adopting multiple combination processes, including solid-liquid separation, air flotation, Anaerobic-Anoxic-Oxic（A₂O）, coagulation and sedimentation. After the expansion and upgrade, the operating cost for the plant is 2.46 yuan/m³; the unit mud production is reduced by about 17.5% and the effluent water quality of chemical oxygen demand（COD）, ammonia nitrogen（NH₃-N）, total phosphorus（TP）, and suspended solids（SS） meets the class A standard in “Discharge standard of pollutants for municipal wastewater treatment plant”（GB18918-2002）. The engineering practice results showed that the process had the advantages of high treatment efficiency, low operating cost, less mud production per unit, and stable operation, which can meet the requirements of wastewater treatment and has good environmental and economic benefits.