This application discloses a method for obtaining a network slice. The method includes: receiving, by a control device, a slice request sent by a user, where the slice request includes an identifier, and the identifier is used to identify isolation information of a slice requested by the user; obtaining, by the control device, a network slice based on the identifier and a resource topology, where the resource topology is used to describe a network topology and isolation information of N elements in the network topology, the N elements include at least one of a node and a link, N is an integer greater than or equal to 1, and the network slice includes a node and a link that are required for implementing the slice.