In this paper, based on the three-dimensional theory and nonlinear governing equations of electric current density, a one-dimensional dynamic tensile model for piezoelectric semiconductor heterojunction is established. The dynamic responses of the displacement, electric potential and electron concentration are obtained with finite element method and an iterative process. The regulation effect of harmonic loads on GaN/AlN piezoelectric semiconductor heterojunction under open-circuit condition is numerically analyzed. Influences of dynamic loads on I-V characteristics are discussed, and the tuning mechanism of dynamic loads on the I-V characteristic is revealed.