In the last couple of years, there has been particularly growing interest worldwide in exploring ways of finding suitable solutions to clean up oil spills and deal with industrial oily wastewater through use of nanomaterials. Key for the success of these materials is a high separation capacity, with resistance to oil fouling, and that are easily recyclable. Oil/water separation is an interfacial challenge, and novel materials designed to possess special wettability have different interaction and affinity for oil and water, thus can realize the separation. Until now, researches in this field all focus on materials with both hydrophobic and oleophilic properties. However, the oil-removing type of materials is easily fouled even blocked up by oils because of their intrinsic oleophilic property. A novel superhydrophilic and underwater superoleophobic hydrogel coated mesh can selectively separate water from oil/water mixtures effectively and without any extra power.