Orbital angular momentum (OAM) is a natural property of beams with spiral phase. OAM beams with different topological charges are mutually orthogonal. OAM beams can be applied to OAM multiplexing as a new information carrier based on their orthogonality. OAM multiplexing greatly improves the channel capacity and spectrum efficiency without additional bandwidth. Owning to its excellent properties, optical fiber has become the best choice in modern communication network. OAM multiplexing based on optical fiber has attracted widespread concern of researchers. We introduce the basic principle of OAM firstly, and then discuss the research progress of the optical fiber, which is suitable for carrying OAM beam, OAM beam generation and detection methods, related devices and experiments of OAM multiplexing technology and so on. Finally, the existing problems and trends of the current technologies are discussed.