A wireless sensing device includes a wireless transmitter module, a microprocessor unit, and a wake-on unit. The wireless transmitter module is electrically connected to the microprocessor unit and the wake-on unit, respectively. The microprocessor unit is electrically connected to the wake-on unit. When the wireless transmitter module receives a sensing signal from outside and transmits it to the microprocessor unit, the microprocessor unit may enter a hibernation mode or a sleep mode from its previous on-duty mode depending on the level of the sensing signal. When the wireless transmitter module receives a wake-on signal from outside and transmits it to the wake-on unit, the wake-on unit generates a resume-from-hibernation command or a resume-from-sleep command for the microprocessor unit depending on the level of the wake-on signal so as to resume the microprocessor unit.