A channel access method in a wireless communication system and an apparatus for supporting the same are disclosed. Particularly, the method comprises the steps of: transmitting a beacon frame containing a traffic indication map (TIM); and receiving a power pave (PS)-poll frame within a PS-Poll section set in a station (STA), to which downlink data is designated by the TIM, from the STA, wherein the PS-Poll section can be set differently for each STA within the entire PS-Poll section set in all STAs, to which downlink data is designated by the TIM.