Provided is a method for configuring a transmission mode for a backhaul link transmission in a radio communication system including a relay station. The method comprises: a step in which a base station transmits, to the relay station, a relay-physical downlink control channel (R-PDCCH) containing backhaul control information; and a step in which the base station transmits, to the relay station, a relay-physical downlink shared channel (R-PDSCH) containing backhaul data, wherein the R-PDCCH is transmitted in one transmission mode selected from a plurality of predetermined transmission modes, and a reference signal transmitted through the R-PDCCH for the demodulation of the R-PDCCH is determined in accordance with said selected transmission mode.