Disclosed are a method for performing an initial access in a wireless communication system, and an apparatus therefor. Specifically, a method by which a terminal performs an initial access comprises the steps of: receiving, from a base station, configuration information representing one or more physical random access channel (PRACH) configurations; receiving, from the base station, downlink control information including information indicating a specific PRACH configuration among the one or more PRACH configurations, through a physical downlink control channel; and transmitting a preamble and/or data, which are related to the initial access, to the base station through a PRACH on the basis of the specific PRACH configuration.