A signal transmission method, comprising: receiving (S104, S204, S304, S404), by a first device , resource configuration information for a reference signal sent by a second device , wherein the reference signal is used to measure interference between a first link and a second link, the first link is an access link between the first device and a fourth device that is a terminal, the second link is a backhaul link between the second device and a third device , and the first device and the second device are relay nodes between the third device and the fourth device ; and sending or receiving (S106, S206, S306, S406), by the first device , the reference signal on a reference signal resource indicated by the resource configuration information for the reference signal, wherein the method further comprises: sending, by the first device , first reporting information to the second device , wherein the first reporting information is used to indicate whether the first device has a multi-link beam correspondence capability; the multi-link beam correspondence capability comprises at least one of the following: a capability of the first device to send or receive, on the first link and a third link, reference signals on antenna ports having a quasi co-location, QCL relationship; or a capability of the first device to send or receive reference signals on the first link and a third link by using a same beam or a same spatial filter; and a backhaul link between the second device and the first device is the third link. receiving (S104, S204, S304, S404), by a first device , resource configuration information for a reference signal sent by a second device , wherein the reference signal is used to measure interference between a first link and a second link, the first link is an access link between the first device and a fourth device that is a terminal, the second link is a backhaul link between the second device and a third device , and the first device and the second device are relay nodes between the third device and the fourth device ; and sending or receiving (S106, S206, S306, S406), by the first device , the reference signal on a reference signal resource indicated by the resource configuration information for the reference signal, wherein the method further comprises: sending, by the first device , first reporting information to the second device , wherein the first reporting information is used to indicate whether the first device has a multi-link beam correspondence capability; the multi-link beam correspondence capability comprises at least one of the following: a capability of the first device to send or receive, on the first link and a third link, reference signals on antenna ports having a quasi co-location, QCL relationship; or a capability of the first device to send or receive reference signals on the first link and a third link by using a same beam or a same spatial filter; and a backhaul link between the second device and the first device is the third link. a capability of the first device to send or receive, on the first link and a third link, reference signals on antenna ports having a quasi co-location, QCL relationship; or a capability of the first device to send or receive reference signals on the first link and a third link by using a same beam or a same spatial filter; and a backhaul link between the second device and the first device is the third link. <EOS>