According to one embodiment of the present invention, a method by which a station (STA) performs channel access in a wireless LAN system comprises the steps of: receiving, from an access point (AP), a first frame indicating whether to deactivate a basic service set (BSS) color; receiving a second frame including a signal (SIG)-A field having a transmission opportunity (TXOP) period subfield and a BSS color subfield; and performing channel access, wherein the STA can perform the channel access by invoking an extended inter-frame space (EIFS) operation when the BSS color is deactivated by the first frame, but the BSS color subfield of the second frame includes the deactivated BSS color and the TXOP period subfield of the second frame includes a valid TXOP period value.