After conducting a lot of screening experiments the appropriate flocculating formulations for treating high-con-centration wastewater discharged fiom a certain refinery were selected. The oil removal rate and COD removal achieved by these flocculating formulations were better than that achieved by the conventional compound formulation consisting of polyaluminium chloride (PAC) and polyactylamide (PAA). Addition of an oil/water separating agent to the formulation could improve its oil removal performance to facilitate the oil/water separation of the oil-in-water emulsion in the high-concentra-tion wastewater along with improved adaptability of the formulation to the wastewater containing high concentration of pollutants. This flocculating agent has promising prospects for commercial application.