Micro accelerometer is used to sense the acceleration of the object and provide velocity and displacement information. The finite element analysis of a silicon based micro piezoresistive high g(g=9.8 m/s2) acceleration sensor in the impact environment has been carried out in this work. The results show that the design of the high g micro piezoresistive accelerometer can properly and effectively work in the 15×104g range, and can withstand high speed impact of 40×104 g. When the acceleration exceed 40.8×104 g, the acceleration sensor failure deformation occurs. The main failure modes and failure mechanisms of micro accelerometer in shock environment have been analyzed, the results show that the main failure modes of the micro accelerometer in shock environment are to start with the border and mass connections from the beam, with the impact of time that increases the intensity of the impact of structural stress gradually reaches the yield limit, the material yield effects occur, then fracture.