Embodiments of the present invention provide a method for controlling UE to access a communications network of a high-speed moving vehicle, a core network control plane node device, a base station, UE, and a communications system. The method includes: determining that UE accessing the communications network is first-type UE, allocating a temporary identifier that includes a first sequence to the UE, and sending the temporary identifier to the UE, where when the UE accesses a public network, the first sequence is used to instruct the base station to transfer the UE to the communications network. In the embodiments of the present invention, user experience of the UE is improved.