A handover method, wherein the method comprises: receiving, by a target radio access network RAN node, a handover message from a network node, wherein the handover message comprises an identifier of at least one source network slice, and the handover message further comprises at least one of the following: an indication indicating whether at least one protocol data unit PDU session of each of the at least one source network slice supports network slice re-mapping, and an indication indicating whether at least one PDU session of each of the at least one source network slice supports network slice fallback; performing, by the target RAN node, admission control based on the handover message, wherein the admission control is used to determine whether to perform network slice re-mapping on the at least one PDU session, and determine an identifier of a network slice to which the at least one PDU session is re-mapped; or the admission control is used to determine whether to fall back the at least one PDU session to a default network slice; and sending, by the target RAN node, a response message to the network node, wherein when the handover message comprises the indication indicating whether the PDU session supports network slice re-mapping, the response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an identifier of a network slice to which a part or all PDU sessions of the at least one PDU session are re-mapped; when the handover message comprises the indication indicating whether the PDU session supports network slice fallback, the response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an indication indicating whether a part or all PDU sessions of the at least one PDU session fall back to the default network slice; or when the handover message comprises the indication indicating whether the PDU session supports network slice re-mapping and the indication indicating whether the PDU session supports network slice fallback, the second response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an identifier of a network slice to which a part or all PDU sessions of the at least one PDU session are re-mapped, or the second response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an indication indicating whether a part or all PDU sessions of the at least one PDU session fall back to the default network slice. receiving, by a target radio access network RAN node, a handover message from a network node, wherein the handover message comprises an identifier of at least one source network slice, and the handover message further comprises at least one of the following: an indication indicating whether at least one protocol data unit PDU session of each of the at least one source network slice supports network slice re-mapping, and an indication indicating whether at least one PDU session of each of the at least one source network slice supports network slice fallback; performing, by the target RAN node, admission control based on the handover message, wherein the admission control is used to determine whether to perform network slice re-mapping on the at least one PDU session, and determine an identifier of a network slice to which the at least one PDU session is re-mapped; or the admission control is used to determine whether to fall back the at least one PDU session to a default network slice; and sending, by the target RAN node, a response message to the network node, wherein when the handover message comprises the indication indicating whether the PDU session supports network slice re-mapping, the response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an identifier of a network slice to which a part or all PDU sessions of the at least one PDU session are re-mapped; when the handover message comprises the indication indicating whether the PDU session supports network slice fallback, the response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an indication indicating whether a part or all PDU sessions of the at least one PDU session fall back to the default network slice; or when the handover message comprises the indication indicating whether the PDU session supports network slice re-mapping and the indication indicating whether the PDU session supports network slice fallback, the second response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an identifier of a network slice to which a part or all PDU sessions of the at least one PDU session are re-mapped, or the second response message comprises the identifier of the at least one source network slice, an identifier of the at least one PDU session of each of the at least one source network slice, and an indication indicating whether a part or all PDU sessions of the at least one PDU session fall back to the default network slice.