The luminance and luminous efficiency was investigated in new structure of AC plasma display panel with the large gap between the front electrodes under a high Xe gas mixture when adopting the proposed driving waveform. As an electrode was far from the other on the front plate comparing to the conventional structure, the driving waveform, especially in the reset and sustain period, should be modified. Therefore, during the reset period, the negative voltage was applied to the sustain electrode to produce the surface discharge between the scan and sustain electrodes. In addition, the sustain waveform was also modified to induce the surface discharge between the front plates after the triggering was made between the front and rear plates. As a result, when the modified driving waveform with the positive sustain voltage of 140V and negative triggering voltage of -110V during a sustain period applied to the panel with Xe gas mixture of 15% and the sustain gap of 500 um, the luminance of 340 cd/m(2) and luminous efficiency of 3.26 lm/W were obtained in the 42-inch AC PDP.