A method for transmitting a reference signal by a Base Station (BS) in a mobile communication system using beamforming includes determining beamforming information for transmission of a Reference Signal (RS) Transmit (Tx) beam, wherein at least one of a Tx period and a beam width of the RS Tx beam is determined differently based on a size of Receive (Rx) areas in which a plurality of Tx beams are received in coverage of the BS; and transmitting the RS Tx beam to related Rx areas depending on the determined beamforming information.