A method, system and device for transmitting and detecting control signaling in a backhaul link are disclosed in the present application, and the application relating to the wireless communication field is used for saving time-frequency resources occupied by a base station for transmitting the control signaling on a Relay Physical Downlink Control Channel (R-PDCCH) of the backhaul link and reducing the complexity of the R-PDCCH detection by a relay node. In the present application, the base station, according to the preset correspondence between the control signaling and the R-PDCCH resource sub-regions, determines the R-PDCCH resource sub-region corresponding to the control signaling to be transmitted among a plurality of resource sub-regions included in the resource region occupied by the R-PDCCH; the control signaling to be transmitted is transmitted to the relay node by using the time-frequency resources in the determined R-PDCCH resource sub-region; the relay node acquires the location information of the R-PDCCH resource sub-region and detects the control signaling to be transmitted in the R-PDCCH resource sub-region according to the location information. With the present application, the time-frequency resources occupied by the base station for transmitting the control signaling on the R-PDCCH are saved and the complexity of the R-PDCCH detection by the relay node is reduced.