According to the vibration fatigue problem of piezoelectric vibration energy harvester, the effects of fatigue damage on the power generating ability of piezoelectric cantilever beams was studied. Taking the piezoelectric cantilever beam used in the piezoelectric vibration energy harvester as the study object, the strain response and the voltage response of the specimens were measured by using sweeping frequency modal test and support motion vibration test. By analyzing the experimental data, the influences of the acceleration and the exciting frequency of support motion on the strain response and the voltage response were discussed. The impacts of fatigue damage on the voltage response of the specimen were studied through the strain response and the voltage response of the specimen before and after 500 000 times of fatigue cycle loading. The results show that different support motion have different effects on the fatigue damage of piezoelectric cantilever beam, and the variation of voltage response of piezoelectric cantilever beam is almost positively correlated with the variation of fatigue strain response caused by fatigue damage.