The shear-mode piezoelectric energy harvester(PEH)offers potentially improved energy harvesting due to higher d15 piezoelectric coefficient than other modes. An L type base PEH based on d15 mode was designed in this paper. The comparison between the L type structure and the upright structure are carried out through the finiteelement simulation analysis. It is shown that the performance of L type PEH are basically the same as upright PEH when the resonance does not occur, and there is a stable energy output over a very wide band; while the output power of L type PEH has increased substantially at the first order modal frequency.An L type base PZT-51PEH prototype based on d51 mode is fabricated. The measured results show that the resonant frequency of PEH is 86 Hz, the output power is 31.25 μW with the acceleration of 2.5g (g=9.8 m/s2) at the matching load of 203 kΩ, and the corresponding power density is 84 μW?cm-3 at the unit gravity acceleration.