A link maintenance method, comprising: determining, by a first node, a candidate neighboring node to be measured, wherein the first node is a relay node, wherein the candidate neighboring node is a neighboring node that is determined to perform measurement; measuring, by the first node, the candidate neighboring node; determining, by the first node based on a measurement result, whether to establish a backup backhaul link between the first node and the candidate neighboring node; and sending, by the first node, a request to a second node, wherein the request is used to request the second node to establish the backup backhaul link between the first node and the candidate neighboring node; wherein the second node is a donor base station or a parent node of the first node, further comprising: receiving (S602(a)), by the first node, a measurement result that is of a potential neighboring node and that is sent by a terminal, wherein the measurement result of the potential neighboring node is used by the first node to determine the candidate neighboring node, wherein the potential candidate neighboring node is used as the candidate neighboring node when the measurement result meets a given threshold, configured by the second node, wherein the potential neighboring node is a neighboring node of the cell in which the first node is located. determining, by a first node, a candidate neighboring node to be measured, wherein the first node is a relay node, wherein the candidate neighboring node is a neighboring node that is determined to perform measurement; measuring, by the first node, the candidate neighboring node; determining, by the first node based on a measurement result, whether to establish a backup backhaul link between the first node and the candidate neighboring node; and sending, by the first node, a request to a second node, wherein the request is used to request the second node to establish the backup backhaul link between the first node and the candidate neighboring node; wherein the second node is a donor base station or a parent node of the first node, further comprising: receiving (S602(a)), by the first node, a measurement result that is of a potential neighboring node and that is sent by a terminal, wherein the measurement result of the potential neighboring node is used by the first node to determine the candidate neighboring node, wherein the potential candidate neighboring node is used as the candidate neighboring node when the measurement result meets a given threshold, configured by the second node, wherein the potential neighboring node is a neighboring node of the cell in which the first node is located. receiving (S602(a)), by the first node, a measurement result that is of a potential neighboring node and that is sent by a terminal, wherein the measurement result of the potential neighboring node is used by the first node to determine the candidate neighboring node, wherein the potential candidate neighboring node is used as the candidate neighboring node when the measurement result meets a given threshold, configured by the second node, wherein the potential neighboring node is a neighboring node of the cell in which the first node is located.