<p>Researches on the flexoelectric effects have been attracted much attention in recent years. Large amounts of the existing contributions mainly concentrate on the experiments and the theorizations of flexoelectric materials. However, the improvement on the performance of flexoelectric materials cannot be studied in the view of the reliability size optimization theories. Based on this, the reliability optimization design of the multi-state flexoelectric structures is proposed through considering the parameter uncertainties. Meanwhile, the performance of the traditional deterministic optimization strategy is also employed to be compared with that of the reliability optimization design. Sequentially, the deterministic optimization model and the reliability optimization model of the electrical output responses are respectively established under multiple electrical states. Then the deterministic optimization strategy of the flexoelectric structures can be performed via the sequential quadratic programming (SQP), and the reliability optimization strategy can be calculated through using the double-layer method. Besides, the performance of the electrical output responses can be enhanced with the reliability optimization strategy. The results provide a reference selection for both of the design and the manufacture of flexoelectric structures, and lay a theoretical foundation for designing the devices in future.</p>