Method for performing positioning in wireless communication system and device therefor

A user equipment (UE) for performing positioning in a wireless communication system, the UE comprising:

• a radio frequency (RF) unit transmitting and receiving a wireless signal;
• and
• a processor functionally connected to the RF unit and controlling the UE,
• wherein the processor performs control to
• receive assistance data including reference cell information and neighbor cell information from a serving base station (BS), the reference cell information and the neighbor cell information including channel state information-reference signal (CSI-RS) configuration information for measurement related to CSI-RS-based positioning,
• receive a CSI-RS from each of a reference cell and at least one neighbor cell on the basis of the received assistance data,
• measure a reference signal time difference (RSTD) regarding the reference cell of the at least one neighbor cell using the received CSI-RS, and
• report the measured RSTD to the serving BS.