To improve the output performances of the linear resonant piezoelectric vibration energy harvester (PVEH), a two-degree of freedom broadband piezoelectric vibration energy harvester (BPVEH) is developed. The experimental setup used to test the BPVEH performances is established. The effects of the stiffness ratio and the load resistor on the output performances of the BPVEH are studied by experiments. The results have shown that BPVEH can not only broaden the operational frequency bandwidth, but also improve the output voltage and the output power by adjusting the stiffness ratio. The bandwidth of the BPVEH is 7 times of the PVEH, and the maximum output power is 4.5 times of the PVEH when the base acceleration is 40 m/s2 and the load resistor is 471 kΩ.