The present disclosure relates to a method, performed by a user equipment (UE), for reporting channel state information (CSI) in a wireless communication system and an apparatus therefor. According to the present disclosure, the UE receives a channel state information reference signal (CSI-RS) from a base station through a multiple antenna port; and reports the CSI to the base station, wherein the CSI includes a precoding matrix indicator for a codebook generated by linear combination, wherein the codebook is generated based on a specific parameter set, and wherein the specific parameter set is differently set/applied based on at least one of a rank value or at least one layer index of a specific rank.