A method of relaying data in a relay station of a wireless communication system based on a radio frame consisting of a plurality of downlink subframes and a plurality of uplink subframes is provided. The method includes receiving, from a base station, a scheduling message at a downlink subframe and transmitting, to the base station, uplink data at a first uplink subframe or a second uplink subframe according to the scheduling message, wherein the first uplink subframe is an uplink subframe shifted by 4 subframes from the downlink subframe, and wherein when the scheduling message includes a scheduling field which indicates decreasing or increasing a time interval between a time of receiving the scheduling message and a time of transmitting the uplink data, the uplink data is transmitted at a second uplink subframe indicated by the scheduling field.