An over-voltage protection device includes a comparison module, a first switch, a second switch and an output switch. The comparison module compares a divided input voltage with a threshold voltage to output a control signal according to the comparison result. The first switch is coupled with the comparison module and controlled by the control signal. The second switch is coupled with the first switch and is controlled by the output signal of the first switch. The output switch is coupled with the second switch, the output switch is coupled with the voltage output terminal, and the output switch is coupled with the voltage input terminal. The output switch is controlled by the output signal of the second switch to cut off the input voltage or pass the input voltage to the voltage output terminal.