In this paper, the microbeam, which incorporates with the mid-plane stretching effect and distributed electrostatic force, is considered. After the beam model is introduced briefly, the governing equation of motion of the microbeam is solved by the energy balance method (EBM). The first and the second order approximate periodic solutions are obtained and plotted for various values of the parameters of the equation. The numerical solutions (Runge-Kutta) are also computed to illustrate good agreement between both results.