Based on the vortex-induced vibration theory and piezoelectric energy harvesting technology， a magnet-enhancement vortex-induced vibration energy harvester （VEH） is proposed， which is more conducive to improve the energy harvesting efficiency for low-velocity water flow. The proposed energy harvester consists of a piezoelectric laminated cantilever beam， a cylindrical bluff body and magnets. First， the energy harvesting characteristics of vortex-induced VEH without additional magnetic force are analyzed by fluid-solid-electrical coupling finite element simulation. Results show that the energy harvesting efficiency is lower in low flow velocity environment. The experimental platform of flow-induced vibration energy harvesting is built， and the energy capture characteristics of magnet-enhancement energy harvester are discussed in detail. Experimental results show that the natural frequency of the piezoelectric energy harvester with transverse repulsion and longitudinal magnetic arrangement is lower， which means that it is easier to vibrate at lower flow velocity and occur vortex-induced resonance. Under the effects of magnetic force， the vibration deformation becomes larger， the output voltage coupled with the vibration frequency bandwidth are therefore improved. As a result， the maximum of output power of the proposed harvester is 120 μW at the flow velocity 0.5 m/s， which is 57.8% higher than that of the VEH without magnet. It shows that the transverse repulsion and longitudinal adsorption magnetic vortex-induced VEH has advances to improving the energy capture efficiency for the lower flow velocity environment.