The acoustic black hole (ABH) in the thin plate structure can reduce the phase velocity of the curved wave, increase the amplitude, and generate high energy density in the acoustic black hole region and energy aggregation effect. Combining ABH with piezoelectric energy harvesting structure, the energy conversion efficiency can be improved. In this paper, the finite element model of piezoelectric energy harvesting structure based on acoustic black hole is established firstly. The kinetic energy density and voltage output characteristics of uniform plate and acoustic black hole structure are compared and analyzed. Based on the finite element method, the equivalent circuit model of piezoelectric vibrator is derived, and the equivalent circuit coupling model of piezoelectric energy harvesting system is established by multisim software. The optimal resistance of the load circuit is determined and the energy harvesting efficiency of the system is improved.