A method for stably operating an FDR mode by a terminal in a wireless communication system supporting the full-duplex radio (FDR) mode comprises the steps of: if a residual self-interference signal is changed to a predetermined threshold or higher in a terminal, transmitting information about the changed residual self-interference signal to a base station; and receiving from the base station a downlink signal on the basis of a modulation and coding scheme (MCS) level that corresponds to the information about the changed residual self-interference signal.