Abstract: Based on the transport mechanism of the single ion radiate plasma, the transient response model of single ion radiate the lateral high-voltage DMOSis proposed. The transient response characters of DMOS at non-junction, single junction and double junction are obtained by the transient response numerical analysis result of the open and close state of the DMOS at different energy ion radiation. Indicated that the peak value drain current of the turn-on state is bigger than that of the turn-off state, the peak value drain current and the arisen time of the peak value drain current are increased while the energy of the ion is increased.