A power-protection apparatus is provided. The apparatus includes an over-voltage protection unit for generating an over-voltage detection signal when the power supply of the load is over the upper limit of a predetermined voltage range; an under-voltage protection unit for generating an under-voltage detection signal when the power supply of the load is under the lower limit of the predetermined voltage range; a working-state detection unit for receiving a control signal and generating a working-state detection signal when the level time-change rate of the control signal is over a time-change rate threshold; and a power-control unit coupled to the over-voltage protection unit, the working-state detection unit and the under-voltage protection unit for controlling the on and off of the power supply according to the over-voltage detection signal, the under-voltage detection signal or the working-state detection signal.