The present invention relates to a wireless communication system and, more specifically, to a method and device for reporting channel state information (CSI). The method by which a terminal in a wireless communication system reports CSI, according to one embodiment of the present invention, can comprise the steps for: receiving a reference signal from a base station; and reporting, to the base station, the CSI generated by using the reference signal. When the CSI for a two-dimensional antenna structure defined by a first domain and a second domain includes a channel quality indicator (CQI) for the two-dimensional antenna structure without including a precoding matrix indicator (PMI) for the two-dimensional antenna structure, the CQI can be calculated on the basis of the tilting in the second domain.