In a Plasma Display Panel (PDP) power control apparatus, an internal voltage of a power supply is detected, and a determination is made as to whether an Alternating Current (AC) power input to the power supply has been turned off on the basis of the detected internal voltage. The output of the power supply is controlled according to a predetermined sequence based on a result of the determination to turn off the PDP. The apparatus rapidly and accurately senses that the AC power has been turned off and performs a predetermined power off sequence to prevent damage to a driving circuit and to prevent the picture quality of the PDP from being degraded.