Embodiments of this application relate to a wake-up signal (WUS) detection method and apparatus, to reduce signaling overheads of a network side device. The WUS detection method is as follows: a terminal device detects a terminal device-specific field in a detected WUS. If the terminal device detects the terminal device-specific field in the WUS, and detects that the WUS includes wake-up information for the terminal device, the terminal device determines, by using location information of the terminal device-specific field as a first index, a first physical uplink control channel (PUCCH) resource corresponding to the first index, and sends a first PUCCH, where the first PUCCH includes a first message used to feed back that the wake-up information for the terminal device is received.