Systems and techniques for reporting channel state information (CSI) in a wireless communication system and a device therefor. Particularly, a method for reporting channel state information (CSI) of a terminal in a wireless communication system can include the steps of: measuring a CSI reference signal (CSI-RS) transmitted by means of multi-panels from a base station; and reporting CSI, which is generated on the basis of the CSI-RS measurement, to the base station. If the terminal receives, from the base station, configuration of a CSI report excluding a matrix index for phase calibration between panels, the CSI includes only a first matrix index, for wide-band (WB) panel compensation, and a second matrix index, for subband (SB) panel compensation, and can be calculated by means of the first matrix index, the second matrix index and a particular matrix index associated with the phase calibration between the panels.