The present invention provides a method: obtaining background noise of a wakeup region on a fingerprint sensor in a terminal device, where the wakeup region is a region for detecting whether the fingerprint sensor is touched; adding a preset safety margin to the background noise, to obtain a first threshold; and determining, according to the first threshold and a preset safety value, an interrupt threshold for the fingerprint sensor to generate an interrupt signal, where the interrupt threshold is used to instruct the fingerprint sensor to generate an interrupt signal, so as to wake up a central processing unit CPU of the terminal device, and the safety value is used to prevent the fingerprint sensor from erroneously triggering an interrupt signal to wake up the CPU.