This application relates to the field of communications technologies, and provides a link maintenance method and an apparatus in a relay system, to reduce a service interruption latency, or to avoid service congestion. The method includes: determining, by a first node, one or more candidate neighboring nodes to be measured; measuring, by the first node, the one or more candidate neighboring nodes; determining, by the first node based on a measurement result, whether to establish or delete a backup backhaul link between the first node and the one or more candidate neighboring nodes; and sending, by the first node, a request to a second node, where the request is used to request the second node to establish or delete the backup backhaul link between the first node and the one or more candidate neighboring nodes.