Misfiring is usually observed at high ambient temperature in plasma display panel (PDP). This leads to bad image quality and limits the productivity of PDP industry. In this paper, experimental observations and improvement on the misfiring at high ambient temperature have been studied. In order to reduce the high ambient temperature misfiring different slope of ramp erase pulse corresponding to the temperature are applied. The experimental results show that the suggested method is quite effective for reducing the high temperature misfiring phenomena.