In order to investigate the application of direct flexoelectric effect, a model of flexoelectric energy harvester based on the simply supported flexoelectric plate was established. Firstly, the dynamic response of the simply supported plate was derived when subjected to point loading excitation. Secondly, according to the direct flexoelectric effect, the energy harvesting theory induced by the dynamic strain gradient is established, and the expression of output voltage and power at both ends of the external load resistance are derived. Finally, the effects of different parameters, such as mode shape, point loading excitation location, flexoelectric patch size, thickness and location, and loading resistance and so on, on the output voltage and power were analyzed. The results show that the output power of the flexoelectric energy harvesting was affected by different vibration mode, patch location, flexoelectric patch thickness and so on. The analysis results have practical significance for optimizing the energy output of the flexoelectric electrical energy harvester with plate structure.