To enhance the hydrophilicity, the surface of polysulfone membrane was modified by UV-irradiation induced coating of HEMA in the presence of AIBN as free radical source. The permeation characteristics of oily water through the surface-modified membrane were investigated. The fluxes of wastewater with oil concentrations of 100 ppm, 200 ppm and 400 ppm through an un-coated membrane were 0.123, 0.081, and 0.076 g/cm2·min, respectively. However, the fluxes through the surface-modified membrane were 0.253, 0.242, and 0.173 g/cm2·min, respectively. The fluxes through the surface-modified membrane were much higher than those through an un-coated membrane: 2.1, 3.0 and 2.3 times higher fluxes. The rejection of oil emulsions by the membrane was higher than 99%. The membrane with HEMA-modified surface, which has a higher flux and less fouling than an original polysulfone membrane, may be a promising candidate for wastewater treatments as well as oily wastewater treatments.