The present disclosure illustrates an electronic device with wake on voice function and an operating method thereof. The electronic device detects an audio signal in analog form by an additional pre-signal detector, and the pre-signal detector wakes up an analog-to-digital converter and a human voice detector when the audio signal in analog form is determined to satisfy a predetermined condition. When a host system of the electronic device enters into a sleep mode from an operation mode, the analog-to-digital converter and the human voice detector enter into a sleep mode together.