Frequent marine oil spills accidents and the increasing discharge of various industrial sewage have caused great threats to the ecological environment and human health. Therefore, it’s a vitally important task for scientists all over the world to develop advanced materials for separating oil/water emulsions. The separation of oil/water emulsion(also known as emulsified oil/water) is more arduous than that of the immiscible oil/water mixture. This review focuses on the materials of oil/water emulsion separation. Firstly, the formation mechanism and the separation principle of oil/water emulsion are analyzed in essence, and we emphasize the importance of "size sieving" effect and membrane demulsification technology. Then, the latest developments of advanced materials which are commonly applied to the separation of oil/water emulsion are comprehensively introduced and discussed from the perspective of substrate, and the application of various modification methods of substrates in oil/water separation are elaborated. The emphases of material modification are "appropriate pore size" and "special wettability", which can meet excellent separation efficiency, permeability, antifouling ability, mechanical ability and durability requirements. These properties are critical for actual oil/water separation operations. Importantly, the environmental system will be getting more complicated in the future. Besides, most of the oil/water emulsions contain a variety of pollutants in the real environment, and most of them are operated in a harsh environment. Therefore, oil/water separation materials need to be constantly improved to meet these conditions. We believe that in the future, an advanced multifunctional material, which can be used for efficient separation of various oil/water emulsions and other impurities under harsh conditions, will possess great prospects.