The present application discloses a signal transmission method, includes: obtaining, by the detection device, port information and switch information of the at least one antenna line device, and port information and switch information of the antenna; sequentially controlling, by the detection device based on the switch information, at least one switch of the at least one antenna line device to perform state switching, performing port scanning, and recording a scanned port and a corresponding switch state; and determining, by the detection device, a port connection relationship of devices in the radio frequency network based on port and switch state information obtained after a plurality of times of state switching and a plurality of times of port scanning, and the port information. Therefore, the detection device controls switch switching of the devices in the radio frequency network to obtain the port connection relationship of the devices in the radio frequency network.