Abstract: Traditional piezoelectric vibration energy harvesters can only collect vibration energy within a relatively narrow resonant frequency band.In order to expand the efficient energy harvesting bandwidth of piezoelectric vibration energy harvesters, a magnetically coupled structure is introduced into a piezoelectric energy harvester with E-type cantilever double-beam.A nonlinear dynamic model of the piezoelectric vibration energy harvester is established based on the principle of energy and analytical mechanics.The effects of acceleration excitation, magnet mass, and magnet spacing on the vibration characteristics of the cantilever beam and the output voltage of the piezoelectric layer are studied and compared with the non-magnetically coupled linear system.The results show that the magnetic coupling force can make the system generate bistable nonlinear vibration, which can effectively expand the energy harvesting bandwidth and increase the output voltage, under the appropriate magnetic field spacing, the bandwidth of the piezoelectric energy harvester has been expanded by nearly four times, and make the system gain higher energy harvesting efficiency than the linear structure.Meanwhile, appropriate acceleration excitation can trigger the transition motion between the potential wells of the cantilever beams, thereby achieving a larger voltage output.And under specific external incentives, reducing the end-mass ratio will enable the collector to collect energy over a wider frequency band.