Abstract: The paper describes the explosion electron emission resulted from microwave radiation field in microwave tube, including the analysis of alternating field-emission and the temperature distribution on the whisker. The deduced equation provides the heating speed of the whisker, besides the relation of produced plasma intensity with amplitude of microwave, electric conductivity, thermal conductivity, mass density and specific heat capacity. When the time is much longer than the period of microwave, the whisker temperature increases linearly with time. The rise ratio of the temperature can reach 3.22×1010 ℃/s, and the whisker may gasify and form plasma in a timescale of hundred nanoseconds.