Suffering from terrible membrane fouling and flux decline caused by foulants absorption or plugging, conventional ultrafiltration membranes are hampered in treating oil/water emulsions. In this work, a novel superhydrophilic/underwater superoleophobic polyacrylonitrile (PAN) ultrafiltration membrane is prepared by a hydroxylamine-induced phase inversion process. The obtained PAN membrane displays a high flux ranging from 2200 to 3806 L m^-2 h^-1 bar^-1 and desirable separation efficiency for various oil in-water emulsions. Additionally, the PAN membrane shows superior antifouling property and recyclability due to its ultralow-oil-adhesion property. Therefore, the superhydrophilic/underwater superoleophobic PAN ultrafiltration membrane provides a promising potential for treating oily wastewater.