Inspired by the superhydrophobic and superhydrophilic properties of the animal or plant surfaces in nature, biomimetic superwetting membranes as a new kind of oil-water separation material has attracted widespread attention from scientific researchers due to its tremendous development potential and broad application prospects in the field of oil-water separation. The basic theoretical models affecting the surface wettability of membrane materials were discussed by analyzing the Young equation, Wenzel model and Cassie model. The two key factors affecting the preparation of the superwetting membranes were summarized as the surface tension and hierarchical micro/nanostructures. Therefore, the superwetting membranes are fabricated by two main ways:designing nano/micro-hierarchical structures on hydrophobic or hydrophilic surfaces and modifying rough surfaces with low or high surface energy materials. Up to now, various approaches have been reported for the preparation of superwetting membranes, including electrospinning, plasma etching, chemical vapor deposition, solution immersion method, electrochemical deposition, etc.