A piezoelectric energy hunting device and a voltage signal application system thereof are disclosed. The piezoelectric energy hunting device includes a plurality of curved piezoelectric elements, a plurality of rigid foams, and a flexible foam structure. The plurality of curved piezoelectric elements are arranged side by side with one another, wherein each curved piezoelectric element is attached to one of the rigid foams. The flexible foam structure includes a top foam and a bottom foam covering the outer surface of the plurality of curved piezoelectric elements and the plurality of rigid foams; when the flexible foam structure is compressed, the plurality of curved piezoelectric elements are simultaneously deformed, thereby generating a voltage signal. When the flexible foam structure is not compressed, the flexible foam structure and the plurality of rigid foams provide an elastic force to restore the plurality of curved piezoelectric elements.