The finite element method was used to study the problem of tensile vibration of p-type GaN piezoelectric semiconductor rod under the action of simple harmonic force. Numerical solutions for the nonlinear dynamic responses of displacement, electric potential and hole concentration were obtained. The modulating effect of simple harmonic force on p-type GaN piezoelectric semiconductor rod was analyzed. The results show that the simple harmonic force significantly affects the distribution of physical fields in the rod. 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 electric fields exhibit periodic variations driven by the simple harmonic force. However, the dynamic response of hole concentration exhibits significant asymmetric fluctuations.