Ul mu transmission method of sta operating in power save mode, and device for performing method

A UL MU transmission method of an STA operating in a power save mode, and a device for performing the method are disclosed. The UL MU transmission method of an STA operating in a power save mode can comprise the steps of: transmitting, by a STA, a TWT request element to an AP; receiving, by the STA, a TWT response element from the AP as a response to the TWT request element, wherein the TWT response element includes information on a target wake time; switching, by the STA, from a dose state to an awake state on the basis of the target wake time so as to receive a beacon frame from the AP; receiving, by the STA, a trigger frame from the AP on the basis of TWT information of the beacon frame; and transmitting, by the STA, an uplink frame to the AP on the basis of the trigger frame by using an UL MU transmission.