With the rapid development of Internet technology, the existing routing system has been confronting many serious challenges of scalability, mobility, multi-homing and traffic engineering. Based on the idea of Identifier/Locator Split, the concept of identifier-based routing is proposed, and its research scope is accurately defined in this paper. On the basis of the design goals of identifier-based routing, some related researches are introduced and compared. Finally, some key issues and the development trends are discussed.