A network slice determining method, comprising: obtaining, by a network selection function, NSF, node, an identity of a terminal; sending, by the NSF node, the terminal identity to a home subscriber server, HSS; receiving, by the NSF node, a slice identifier of a network slice that is sent by the HSS, wherein the slice identifier is determined by the HSS based on the terminal identity; and determining, by the NSF node based on the slice identifier, the network slice to which the terminal belongs, wherein the NSF node stores a correspondence between the slice identifier of the network slice and network slice attribute information, and wherein the network slice attribute information comprises at least one of a terminal type, a service type, and a location range that are supported by a network slice corresponding to the network slice attribute information; and the determining, by the NSF node based on the slice identifier, the network slice to which the terminal belongs comprises: querying, by the NSF node based on the slice identifier of the network slice network slice attribute information corresponding to the slice identifier; obtaining, by the NSF node, assistance information from the terminal, wherein the assistance information comprises at least one of a terminal type of the terminal, a service type requested by the terminal, and location information of the terminal; and if the assistance information matches the network slice attribute information, determining, by the NSF node, a network slice indicated by the slice identifier as the network slice to which the terminal belongs. obtaining, by a network selection function, NSF, node, an identity of a terminal; sending, by the NSF node, the terminal identity to a home subscriber server, HSS; receiving, by the NSF node, a slice identifier of a network slice that is sent by the HSS, wherein the slice identifier is determined by the HSS based on the terminal identity; and determining, by the NSF node based on the slice identifier, the network slice to which the terminal belongs, wherein the NSF node stores a correspondence between the slice identifier of the network slice and network slice attribute information, and wherein the network slice attribute information comprises at least one of a terminal type, a service type, and a location range that are supported by a network slice corresponding to the network slice attribute information; and the determining, by the NSF node based on the slice identifier, the network slice to which the terminal belongs comprises: querying, by the NSF node based on the slice identifier of the network slice network slice attribute information corresponding to the slice identifier; obtaining, by the NSF node, assistance information from the terminal, wherein the assistance information comprises at least one of a terminal type of the terminal, a service type requested by the terminal, and location information of the terminal; and if the assistance information matches the network slice attribute information, determining, by the NSF node, a network slice indicated by the slice identifier as the network slice to which the terminal belongs. querying, by the NSF node based on the slice identifier of the network slice network slice attribute information corresponding to the slice identifier; obtaining, by the NSF node, assistance information from the terminal, wherein the assistance information comprises at least one of a terminal type of the terminal, a service type requested by the terminal, and location information of the terminal; and if the assistance information matches the network slice attribute information, determining, by the NSF node, a network slice indicated by the slice identifier as the network slice to which the terminal belongs.