Abstract: A plasma display panel (PDP), and more particularly, an apparatus for discharging the PDP with a time-lag by a horizontal line, thus reducing instantaneous power consumption, and a method thereof, are provided. The apparatus for discharging the PDP with the time-lag includes a signal processor for separating a vertical synchronous signal of a horizontal line from a received video signal and delaying the vertical synchronous signal of the horizontal line in order to delay the discharge time of a next horizontal line, a data controller for generating a discharge pulse for discharging pixels of the horizontal line according to the vertical synchronous signal, and a discharge pulse for discharging pixels of the next horizontal line according to the delayed vertical synchronous signal, and a displayer for discharging the horizontal line and the next horizontal line by the discharge pulses with the time-lag and displaying the horizontal lines.