The finite element model of cantilever piezoelectric vibration energy harvester is established. Its first order natural frequency is solved by modal analysis and an experiment verifies the accuracy of the result. The static analysis of the established finite element model is carried out, then the results is conducted into ANSYS nCode DesignLife for fatigue analysis. The results show that with the increase of excitation displacement amplitude, the strain of piezoelectric layer increases linearly but the fatigue life shortens rapidly. When the excitation displacement doubles, the fatigue life is reduced as much as 284 times. Therefore, the output voltage of piezoelectric cantilever beam and the fatigue life of piezoelectric layer should be considered comprehensively in order to achieve maximum power output.