This specification discloses a method for transmitting a demodulation reference signal (DMRS) in a wireless communication system supporting NB (Narrow-Band)-IoT (Internet of Things), the method performed by a User Equipment (UE) including generating a reference signal sequence used for demodulation; mapping the reference signal sequence to at least one symbol; and transmitting the demodulation reference signal (DMRS) to a base station through a single subcarrier in the at least one symbol.