A method by which a terminal transmits a data channel in a wireless communication system is disclosed. Particularly, in the disclosure, a plurality of reference signals are transmitted through a plurality of transmission beams within a first frequency band, first information related to the reception quality of at least one reference signal from among the plurality of reference signals is received within a second frequency band, a transmission beam through which the data channel is to be transmitted is determined on the basis of the first information, and the data channel is transmitted through the transmission beam within the first frequency band, wherein the first frequency band is higher than the second frequency band.