Two-dimensional (2D) materials have emerged as a class of promising materials to prepare highperformance 2D membranes for various separation applications. The precise control of the interlayer nano-channel/sub-nanochannel between nanosheets or the pore size of nanosheets within 2D membranes enables 2D membranes to achieve promising molecular sieving performance. To date, many 2D membranes with high permeability and high selectivity have been reported, exhibiting high separation performance. This review presents the development, progress, and recent breakthrough of different types of 2D membranes, including membranes based on porous and non-porous 2D nanosheets for various separations. Separation mechanism of 2D membranes and their fabrication methods are also reviewed. Last but not the least, challenges and future directions of 2D membranes for wide utilization are discussed in brief.

二维（2D）材料已经成为一类有前途的材料，可以制备用于各种分离应用的高性能2D膜。精确控制纳米片之间的层间纳米通道/亚纳米通道或2D膜内纳米片的孔径可以使2D膜获得有希望的分子筛性能。迄今为止，已经报道了许多具有高渗透性和高选择性的2D膜，表现出高的分离性能。这篇综述介绍了不同类型的2D膜的发展，进展和最近的突破，包括基于用于各种分离的多孔和无孔2D纳米片的膜。还综述了二维膜的分离机理及其制备方法。最后但是同样重要的，