A method for transmitting a data demodulation reference signal (DMRS) in a wireless communication system and a device therefor are disclosed. To this end, a basic DMRS is transmitted via the first OFDM symbol in a data transmission region of a predetermined subframe, and an additional DMRS is transmitted in the predetermined subframe in accordance with a level determined by a transmission environment, wherein the basic DMRS is characterized by being transmitted via the first OFDM symbol in the data transmission region of the predetermined subframe regardless of a transmission link, the structure of the subframe, and the transmission environment.