The present invention relates to transmitting a downlink reference signal in a wireless communication system. A method for a base station to transmit a downlink signal by using two or more layers includes multiplexing and transmitting a reference signal for the two or more layers on the basis of a reference signal pattern on a data region of a downlink subframe and transmitting data for the two or more layers on the data region of the downlink subframe, wherein the reference signal for the two or more layers is a dedicated reference signal that is used to demodulate the data for the two or more layers on a receiving end, and in the multiplexing of the reference signal, the reference signal for the two or more layers is code-division-multiplexed by an orthogonal code having a length of at least 2.