The present invention relates to a wireless communication system, and more specifically, to a method and an apparatus for transmitting an RS (Reference Signal) from a transmission end. The present invention relates to an RS transmission method and an apparatus therefore, comprising the steps of: confirming RS resources which are defined according to each layer; and transmitting the precoded RS for the layers to a receiving end through a multiple antenna, wherein the RS resource includes a 1st index for indicating an RS resource pattern group in which the precoded RS is mapped within a resource block and a 2nd index for indicating a code resource for multiplexing the precoded RSs within the RS resource pattern group.