A fully integrated micro electromagnetic vibration energy harvester based on MEMS technology is designed and its mechanical and electromagnetic characteristics are analyzed by using Finite Element method (FEM). Structure static, modal and harmonic analysis of spring-magnet system was carried out by ANSYS software. Ansoft Maxwell software was used to simulate the electromagnetic characteristics of the energy conversion system, especially the relationship between the output performances of the structure and parameters of the coil. The optimized model is designed and the optimization principles could provide a reference for the future electromagnetic vibration based harvester design.