It was found experimently that the X-ray emission was enhanced from GaAs and Zn plasmas irradiated by a Nd:glass laser pulse with width of 2ns and on target power density of 5 ×1013 W/cm2 in a high frequency electric field in 0.1 Torr air atmosphere. The intensity of X-ray was much stronger in the presence of the high frequency field than that without it. The ratios of the intensity α -I(field)/I(no field) were determined from the obtained spectra, however the plasma temperature deduced from the recombinatition continuum was lower in the presence of high frequency eleotrio field (Te=300 eV) than, that without it (Te=430 eV).