A transverse electromagnetic vibration energy harvester based on Micro-electro-mechanical System(MEMS) was designed to convert the vibration mechanical energy around our environments to electrical powers. It mainly consisted of two vertically polarized rectangle permanent magnets, a mass-spring vibration system with a copper coil and a substrate. The structure parameters of system were analyzed and optimized by Finite Element Analysis (FEA), and a harvester prototype was fabricated. During the fabrication of the harvester, electroplating technology was employed to fabricate a spiral copper coil, KOH wet etching and Deep Reaction Ion Etching(DRIE) technology were employed to fabricate mass-spring vibration system, then the harvester prototype was formed together with permanent magnets. The volume of the harvester was about 100 mm3. The test results for vibration characteristics show that the natural frequency of the mass-spring vibration system is 241 Hz. The electromagnetic vibration energy harvester can generate a peak-peak voltage of 9.2 mV at an external acceleration of 2.8 ms-2 and frequency of 241 Hz. Furthermore, by adjusting the parameters of mass-spring vibration system, the harvester with different natural frequencies can obtained. The havester can convert the mechanical energy to the electrical energy and have significance for the clevelopment and application of the wireless sensor devices.