Abstract: The purpose of this paper is to use the Finite DifferenceTime Domain (FDTD) method to determine numerically the influence of plasma exhaust plume to boost flyer on electromag netic pulse effects. Computational datas indicate that the distribution of the induced skin current is seriously changed by the exhaust plume. The skin current density of the flyer with exhaust plume is quite larger than that of the flyer without exhaust plume. The waveform of the induced current is a decreased ringing wave and the ringing period equals twice to the time of induced current flowing along flyer and exhaust plume.