We experimentally investigate the generation of hot electrons from the interaction of a moderate-intensity(1016W/cm2) pre-pulsed-free femtosecond laser (6m J, 120fs, at 744nm) with a solid target. The temperatureof the hot electrons is inferred from the hard x-ray (＞ 30keV) continuum. The measured hard x-ray continuumis fitted by the Maxwellian distribution with two hot-electron temperatures of 45 and 85keV. Electrons withthe lower temperature were accelerated by "vacuum heating". However it is necessary to carry out an accuratenumerical simulation to explain the generation of hot electrons at higher temperatures.