Abstract:A micro piezoelectric energy harvesting is designed based on a bistable plate that is twolayered square plates fixed in the midpoint of the plates and free at four edges. Based on strain gradient theory, considering the size effect, a micropiezoelectric element is defined using Userdefined Finite Element Subroutine (UEL) in ABAQUS. With the thermalforceelectric coupling analysis method, it is found that there are different deformation shapes under different excitation frequencies. The analysis nonlinear dynamic shows that the structure can change more vibration energy to electric energy before its first natural frequency, and there exists snapthrough behavior in its frequency response range. The optimum working frequency and maximum output voltage are concluded for the micro piezoelectric energy harvesting. The research findings have an important guiding significance for design of micro piezoelectric energy harvesting.