A new type of packing material, polystyrene resin modified by cetyltrimethyl-ammonium bromide (R-CTAB), was developed for separation of emulsified oil wastewater. The unique separation mechanism of the modified resin is due to the hydrogen bond formation between hydrocarbon molecules and the free hydrophilic part of the fixed surfactant. It changed the zeta potential of oil droplets and made them coalescing easier, which provide an optional choice without any chemicals added into the wastewater. A column of R-CTAB was investigated for its performance in separating emulsified oil droplets in oily wastewater. The effects of liquid space velocity and influent oil concentration were studied in particular. The results showed that R-CTAB column was more efficient than the un-modified resin column. Under the optimum experimental conditions, more than 85% of oil was removed by using R-CTAB column that at least 10% higher than the un-modified resin column.