In this paper, the finite element method is used to study the problem of tensile vibration of p-type GaN piezoelectric rod under the action of simple harmonic forces is investigated. Numerical solutions for the nonlinear dynamic responses of displacement, electric potential and hole concentration are solved. The effects of simple harmonic forces on p-type GaN piezoelectric rod are analyzed. The results show that the simple harmonic forces significantly affect the distribution of physical fields. The distributions of the electric field and hole concentration lose their symmetry or anti-symmetry due to the electrically nonlinear term in the current density; the mechanical and electric fields exhibit periodic variations driven by the simple harmonic force. However, the dynamic response of hole concentration exhibits significant asymmetric fluctuations.