A method for transmitting a Channel State Information-Reference Signal (CSI-RS) in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising of determining a CSI-RS pattern type based on a Physical Resource Block (PRB) index of a subframe, assigning, when the subframe is supposed to carry the CSI-RS, CSI-RSs of first to Nth antenna ports to first to Nth Orthogonal Frequency Division Multiplexing (OFDM) symbols of a PRB based on the CSI-RS pattern type, and transmitting the subframe including the PRB in which CSI-RSs of the first to Nth antennas a mapped, wherein the first to Nth CSI-RS pattern types map CSI-RSs of the first to Nth antenna ports to the first to Nth OFDM symbols of the PRB in an alternate manner.