A hard disk power supply protection circuit is used for protecting the hard disk when the motherboard is suddenly powered off. The hard disk power supply protection circuit comprises a first power supply circuit for outputting a first voltage to power the hard disk, and maintaining the output of the first voltage for a first preset time after the motherboard is powered off; a second power supply circuit for outputting a second voltage for supplying power to the hard disk and maintaining the output of the second voltage for the first preset time after the motherboard is powered off. When the motherboard is suddenly powered off, the first power supply circuit and the second power supply circuit respectively output the first voltage and the second voltage to the hard disk in the first presettime, so that the magnetic head of the hard disk moves to the zero track of the hard disk in the first preset time so as to prevent the damage to the hard disk due to the head not being able to move to zero track.