In this paper, an array of permanent magnets is proposed as a floating magnet to enhance the levitation characteristics of the diamagnetic levitation structure. Experimental results show that the maximum steady levitation gap of the diamagnetic levitation structure can be increased by 80.21% with the new floating magnet, and the axial size of the diamagnetic levitation structure can be reduced by up to 39.73%. A prototype of a vibration energy harvester based on the diamagnetic levitation structure was constructed. The experimental results show that when the external excitation frequency is 4.8 Hz and the amplitude is 6 mm, the maximum effective voltage of the vibration energy harvester is 1663 mV. Compared with the original structure, the output performance of the vibration energy harvester is improved by 33.87%. This study shows that using this permanent magnet array as a floating magnet not only improves the levitation characteristics of the diamagnetic levitation structure, but also enhances the output performance of the vibration energy harvester.