A method for obtaining a network slice, wherein the method comprises: receiving, by a control device, a slice request sent by a user, wherein the slice request comprises an identifier, and the identifier is used to identify an isolation level of a slice requested by the user; obtaining, by the control device, an isolation type of the slice based on the identifier; and creating, by the control device, a network slice based on the isolation type of the slice and a resource topology, wherein the resource topology is used to describe a network topology and isolation capabilities of N elements in the network topology, the N elements comprise at least one of a node and a link, N is an integer greater than or equal to 1, and the network slice comprises a node and a link that are required for implementing the slice, wherein the creating, by the control device, a network slice based on the isolation type of the slice and a resource topology comprises: selecting, by the control device from the resource topology based on the isolation type of the slice, a sub-resource topology matching the isolation type of the slice, wherein an isolation capability of a node comprised in the sub-resource topology is the isolation type of the slice, and an isolation capability of a link comprised in the sub-resource topology is the isolation type of the slice; and storing, by the control device, a correspondence between the sub-resource topology and the identifier. receiving, by a control device, a slice request sent by a user, wherein the slice request comprises an identifier, and the identifier is used to identify an isolation level of a slice requested by the user; obtaining, by the control device, an isolation type of the slice based on the identifier; and creating, by the control device, a network slice based on the isolation type of the slice and a resource topology, wherein the resource topology is used to describe a network topology and isolation capabilities of N elements in the network topology, the N elements comprise at least one of a node and a link, N is an integer greater than or equal to 1, and the network slice comprises a node and a link that are required for implementing the slice, wherein the creating, by the control device, a network slice based on the isolation type of the slice and a resource topology comprises: selecting, by the control device from the resource topology based on the isolation type of the slice, a sub-resource topology matching the isolation type of the slice, wherein an isolation capability of a node comprised in the sub-resource topology is the isolation type of the slice, and an isolation capability of a link comprised in the sub-resource topology is the isolation type of the slice; and storing, by the control device, a correspondence between the sub-resource topology and the identifier. selecting, by the control device from the resource topology based on the isolation type of the slice, a sub-resource topology matching the isolation type of the slice, wherein an isolation capability of a node comprised in the sub-resource topology is the isolation type of the slice, and an isolation capability of a link comprised in the sub-resource topology is the isolation type of the slice; and storing, by the control device, a correspondence between the sub-resource topology and the identifier.