Membrane fouling is usually a troublesome issue in oily water treatment, especially containing complex crude oil emulsions. Although most of the reported membranes are in a position to repel models oils, it…s still a big challenge of repelling crude oil. Besides, the fabrication processes of those membranes are too complicated, high-cost and environmentally unfriendly. Hence, in this work, a facile and green method was designed to fabricate a Cellulose nanofiber (CNF) polyelectrolyte filtration membrane with excellent underwater superoleophobic characteristic and outstanding antifouling performance. The membrane not only can separate oil/water emulsions with a high separation efficiency (>99%) and water flux (>11,000 L m-2 h-1), but also remove positively charged dyes with good permeation fluxes (>10,000 L m-2 h-1) and rejection radio (>98%). Herein, it can be anticipated that this method has excellent potential for designing and preparing the specific membranes for multifunctional applications in water treatment.