A d15 mode piezoelectric energy harvester with two PZT 51 elements in series connection was fabricated,in which the PZT 51 elements were arranged along the width direction.The electrical properties of the PEHSC at various frequencies and load resistances were studied systematically.At the frequency of 73 Hz,the maximum output peak to peak voltage and output power of the PEHSC are 12.4 V and 8.7 μW at 2.2 MΩ load resistance.The frequency dependence of the electrical properties is compared with the ANSYS numerical solution,which reveals acceptable agreement.The effects of the proof mass and geometrical dimensions on the energy harvesting performance are discussed to provide some useful guidelines to the design of piezoelectric energy harvesting devices.