The present invention relates to a wireless communication system. A method for reporting CSI (Channel State Information) in a cooperative multi-point (CoMP) wireless communication system, the method performed by a user equipment (UE) and comprising receiving first resource configuration information for a CSI-RS (Channel-State Information-Reference Signal) and second resource configuration information for interference measurement; and calculating CSI using the first resource configuration information and the second resource configuration information, the CSI being for one or more base stations (BSs) among a plurality of BSs participating the COMP, wherein an interference measurement resource according to the second resource configuration information exists in a union of zero-power CSI-RS resources of each of the plurality of BSs.