Provided is a method for operating a power save mode performed by an access point in a WLAN system. The method includes: transmitting, by an access point (AP), a first traffic indication map (TIM) broadcast indication frame to a first station (STA); transmitting, by the AP, a second TIM broadcast indication frame to a second STA; transmitting, by the AP, a first TIM frame indicating that buffered traffic to the first STA is present; and transmitting, by the AP, a second TIM frame indicating that buffered traffic to the second STA is present. The first TIM broadcast indication frame includes a first TIM offset field indicating a transmission time of the first TIM frame, and the second TIM broadcast indication frame includes a second TIM offset field indicating a transmission time of the second TIM frame.