A method for a station (STA), which supports a high efficiency physical layer protocol data unit (HE PPDU), for operating in a power-save (PS) mode in a wireless LAN system according to one embodiment of the present invention comprises the steps of: receiving a PPDU; decoding at least a part of the PPDU; and operating in a doze state until the end of the PPDU on the basis of the result of decoding at least a part of the PPDU, wherein if the PPDU is configured as a very high throughput (VHT) PPDU, which is a legacy format compared to the HE PPDU, and the VHT PPDU is determined to be an uplink frame transmitted to an access point (AP) by another STA belonging to the same basic service set (BSS) as the STA, then the STA can operate in a doze state until the end of the PPDU.