A handover method, comprising: sending, by a first Radio Access Network, RAN, element, a first handover request message to a second RAN element, wherein the first handover request message is a RAN handover request for handover of User Equipment, UE, from a first RAN to a second RAN, and a connection between the first RAN and a first core network are kept unchanged during the handover of the UE from the first RAN to the second RAN, wherein the first RAN element is a source RAN element belonging to the first RAN, the second RAN element is a target RAN element belonging to the second RAN, and the first RAN and the second RAN are different RANs, each corresponding to a different core network type; receiving, by the first RAN element, uplink data of the UE forwarded by the second RAN element, and sending the uplink data of the UE to a first core network element; receiving, by the first RAN element, a handover complete of the UE from the first RAN to the second RAN sent by the second RAN element; and sending, by the first RAN element, a second handover request message to the first core network element, wherein the second handover request message is a core link handover request for handover from the first core network to a second core network and carries a first indication message for indicating that the handover of the UE from the first RAN to the second RAN is completed; wherein the first core network element is a source core network element belonging to the first core network, the second core network element is a target core network element belonging to the second core network, the first RAN and the first core network each belongs to a 5G system or a 4G system, the second RAN belongs to the 4G system or the 5G system different from the first RAN. sending, by a first Radio Access Network, RAN, element, a first handover request message to a second RAN element, wherein the first handover request message is a RAN handover request for handover of User Equipment, UE, from a first RAN to a second RAN, and a connection between the first RAN and a first core network are kept unchanged during the handover of the UE from the first RAN to the second RAN, wherein the first RAN element is a source RAN element belonging to the first RAN, the second RAN element is a target RAN element belonging to the second RAN, and the first RAN and the second RAN are different RANs, each corresponding to a different core network type; receiving, by the first RAN element, uplink data of the UE forwarded by the second RAN element, and sending the uplink data of the UE to a first core network element; receiving, by the first RAN element, a handover complete of the UE from the first RAN to the second RAN sent by the second RAN element; and sending, by the first RAN element, a second handover request message to the first core network element, wherein the second handover request message is a core link handover request for handover from the first core network to a second core network and carries a first indication message for indicating that the handover of the UE from the first RAN to the second RAN is completed; wherein the first core network element is a source core network element belonging to the first core network, the second core network element is a target core network element belonging to the second core network, the first RAN and the first core network each belongs to a 5G system or a 4G system, the second RAN belongs to the 4G system or the 5G system different from the first RAN.