A method and an apparatus for receiving a signal by a terminal in a wireless communication system according to an embodiment of the present invention comprises the steps of: establishing an RNTI associated with an MCS by a terminal; receiving a control channel for scheduling transmission of an uplink data channel or reception of a downlink data channel; and transmitting the uplink data channel or receiving the downlink data channel on the basis of one MCS table of a plurality of MCS tables, wherein the uplink data channel or the downlink data channel has been scheduled by the control channel and the one MCS table is determined on the basis of an RNTI associated with the MCS and an RNTI associated with the control channel.