Disclosed are a method and an apparatus for accessing a channel in a wireless LAN. A method for a station (STA) initially accessing the channel in the wireless LAN comprises the steps of: the STA receiving from an access point (AP) a frame including channel state information and a set of an N (a natural number wherein N>1) number of access parameter sets; the STA selecting a random variable when the channel state information indicates that a wireless link is busy; the STA selecting one access parameter set from the N number of access parameter sets on the basis of the one access parameter and transmitting an association request frame to the AP.