Traditional energy harvesters have problems such as low energy conversion efficiency and narrow operating frequency bands. To obtain a high-performance and low-cost piezoelectric energy harvester, a variable vibration angle dual-end resonance wide-body piezoelectric energy harvester is proposed. This harvester uses a centrally symmetric widened cantilever beam as the vibration carrier, with the clamping end located at the central axis, and works in a mode of mid-span clamping with dual vibration end excitation. The vibration angle is changed by moving the mass block on the wide beam surface, and the dynamic response characteristics of the system are optimized through this design. In this study, a vibration exciter experimental platform was built and an experimental prototype was made to carry out controlled variable experiments. The experimental results show that the harvester has the optimal output power under a certain external resistance; the change of vibration angle can improve the output performance of the harvester; the system output power increases when the mass block increases; at a clamping angle of 20°, excitation acceleration of 0.4g, and frequency of 17.8 Hz, the harvester reaches the optimal output power of 4.66 mW; the output performance and resonant frequency can be changed by altering the length of the force arm, and the operating frequency band can be widened by paralleling multiple devices with different force arms. This study realizes the optimization of dynamic response under the composite deformation of the piezoelectric beam through the centrally symmetric cantilever beam structure and variable vibration angle design, providing a new theoretical basis for vibration energy harvesting.