According to one aspect of the present disclosure, disclosed are a method for a terminal in a wireless communication system, and a device for supporting same, the method including: transmitting message A related to a random access procedure, message A including a physical random access channel (PRACH) preamble and a physical uplink shared channel (PUSCH); and comprising, in response to the message A, message B related to the random access procedure, wherein a demodulation reference signal (DM-RS) for the PUSCH is transmitted based on a DM-RS port, and wherein the number of the DM-RS ports is {1, 2, 4}.