The present invention relates to a plasma display apparatus, and more particularly, to a driving method thereof. The plasma display apparatus includes a panel comprised of a first substrate and a second substrate bonded to each other, a first electrode and a second electrode formed on the upper substrate, and a sustain driver for applying sustain pulses to the first and second electrodes, wherein the sustain driver applies a sustain voltage between the first and second electrodes, and floats at least one of the first and second electrodes after the completion of a sustain discharge caused by the sustain voltage.In the plasma display apparatus and the driving method thereof, according to the present invention, at least one of a scan electrode and a sustain electrode is floated for a predetermined time after the completion of the sustain discharge. This floating state prevents wall charges that are generated during the sustain discharge from being accumulated and increases a discharge path of a plasma display apparatus using a space voltage, thereby improving afterimage characteristic and enhancing brightness and discharge efficiency.