Disclosed is a method by which a terminal reports channel quality information (CQI) to a base station in a multi-antenna-based wireless communication system. Particularly, the method comprises the steps of: receiving, through an upper layer, the reference signal configuration defined by P number of antenna ports; receiving, through M number of antenna ports, reference signals from the base station; grouping the P number of antenna ports into antenna port groups formed of the M number of antenna ports; calculating CQIs by using the reference signal corresponding to each of the antenna port groups on the basis of the assumption that predefined precoders are applied to the reference signals; and reporting, to the base station, N number of CQIs among the calculated CQIs.