A network handover method comprising: determining, by a terminal device, that handover from a first core network to a second core network needs to be performed; and configuring, by the terminal device, a protocol layer according to core network types of the first core network and the second core network; characterized in that the configuring, by the terminal device, the protocol layer according to the core network types of the first core network and the second core network, comprises: when the first core network and the second core network are core networks of different types, updating, by the terminal device, configuration of a packet data convergence protocol, PDCP, layer corresponding to the first core network to configuration of a PDCP layer corresponding to the second core network; updating, by the terminal device, a protocol version of the PDCP layer corresponding to the first core network to a protocol version of the PDCP layer corresponding to the second core network; updating, by the terminal device, configuration of a radio resource control, RRC, layer corresponding to the first core network to configuration of an RRC layer corresponding to the second core network; and switching, by the terminal device, a non-access stratum, NAS, entity from a first NAS entity supporting the first core network to a second NAS entity supporting the second core network; and maintaining, by the terminal device, the configuration of a radio link control, RLC, layer, a media access control, MAC, layer, and a physical, PHY, layer unchanged. determining, by a terminal device, that handover from a first core network to a second core network needs to be performed; and configuring, by the terminal device, a protocol layer according to core network types of the first core network and the second core network; characterized in that the configuring, by the terminal device, the protocol layer according to the core network types of the first core network and the second core network, comprises: when the first core network and the second core network are core networks of different types, updating, by the terminal device, configuration of a packet data convergence protocol, PDCP, layer corresponding to the first core network to configuration of a PDCP layer corresponding to the second core network; updating, by the terminal device, a protocol version of the PDCP layer corresponding to the first core network to a protocol version of the PDCP layer corresponding to the second core network; updating, by the terminal device, configuration of a radio resource control, RRC, layer corresponding to the first core network to configuration of an RRC layer corresponding to the second core network; and switching, by the terminal device, a non-access stratum, NAS, entity from a first NAS entity supporting the first core network to a second NAS entity supporting the second core network; and maintaining, by the terminal device, the configuration of a radio link control, RLC, layer, a media access control, MAC, layer, and a physical, PHY, layer unchanged. when the first core network and the second core network are core networks of different types, updating, by the terminal device, configuration of a packet data convergence protocol, PDCP, layer corresponding to the first core network to configuration of a PDCP layer corresponding to the second core network; updating, by the terminal device, a protocol version of the PDCP layer corresponding to the first core network to a protocol version of the PDCP layer corresponding to the second core network; updating, by the terminal device, configuration of a radio resource control, RRC, layer corresponding to the first core network to configuration of an RRC layer corresponding to the second core network; and switching, by the terminal device, a non-access stratum, NAS, entity from a first NAS entity supporting the first core network to a second NAS entity supporting the second core network; and maintaining, by the terminal device, the configuration of a radio link control, RLC, layer, a media access control, MAC, layer, and a physical, PHY, layer unchanged.