Abstract: Using momentum equation, energy equation and continuity equation of electrons in the upper ionosphere, with the assumption of ambipolar diffusion and β combination of electrons, a theoretical model for heating of the upper ionosphere by powerful high-frequency radio waves is presented. In this paper, these equations are solved numerically to calculate the change of the electron temperature and density at the heights between 150km and 400km in the ionosphere. For specific transmitter’s parameters and specific radio waves energy absorbed model, the calculated results show that the perturbation of the electron temperature and density are obvious. In terms of the selected parameters in this paper, the calculated results show that the electron temperature is increased by about 10%-25%, and the electron density is decreased by 1%-2% or so in the vicinity of the reflective point of radio waves. The time scales of electron temperature to reach its steady state is much faster than that of electron density. Finally, by means of these results, some observed phenomena in many heating experiments are explained in this paper.