The pneumatic system is widely used in industrial production. When it works, the exhaust gas is directly passed into the atmosphere, resulting in wasting a large amount of energy. In this paper, the polyvinylidene fluoride (PVDF) piezoelectric plate is used as the core component of energy harvester to collect energy from the discharged compressed gas. A vibration energy harvester with multi-cantilever beam was designed, and the flow field of compressed gas entering the energy harvester was analyzed by ANSYS finite element simulation software, the power generation effect of piezoelectric plate was tested experimentally. The results show that the diameter of the incident port, the diameter of the spoiler column, the pressure of the incident port and the distance between the incident port and the spoiler column all affect the power generation effect of the piezoelectric plate. When the incident port pressure is 80 kPa and the load resistance is 900 kΩ, the total power of the energy harvester is up to 120.64 μW, which is 28.8% higher than that of other harvesters.