A voice wake-up device includes a microphone module, an electrical connector, and a microcontroller unit. The microcontroller unit includes at least one microcontroller and a memory for storing microcontroller-executable instructions. The microcontroller-executable instructions enable the microcontroller unit to execute multiple tasks including detecting whether a sound signal is in ambient sounds received by the microphone module, and generating an input sound signal according to the sound signal; determining whether the input sound signal includes a predetermined wake-up voice; and confirming the predetermined wake-up voice is comprised in the input sound signal and outputting a wake-up instruction to wake up the electronic device entering the non-hibernation mode from the hibernation mode.