A method by which a terminal reports channel state information (CSI) in a wireless communication system, according to an embodiment of the present specification, comprises the steps of: receiving configuration information related to reporting of CSI; receiving a channel state information-reference signal (CSI-RS); calculating the CSI on the basis of the CSI-RS; and reporting the CSI. The CSI comprises first information for selecting an antenna port related to the CSI-RS. The pre-set number of antenna ports are selected for each antenna port-related polarization from among antenna ports related to the CSI-RS, on the basis of the first information. The pre-set number of antenna ports are characterized in being selected on the basis of a combination of the number of the antenna ports related to the CSI-RS and the pre-set number.