Abstract: The dynamic response of the packagestructure for a high-g MEMS accelerometer with double cantilever beams under high-g shock acceleration was simulated using finite element method.By applyinghalf sine pulse of acceleration with 100,000 g’ speak,it is found that the effect of modulus of encapsulant on the simula ted output voltage and beam deflection can be ignored.The peak value of output voltage is close to the analytic solution.The cantilever beams of accelerometer behave as forced vibration,with the cantilever beams ’ natural characteristic frequency under damping.But the peak values of output voltage and beam deflection show good linearity with peak acceleration applied.Encapsulant with elastic modulus above 4GPa is rigid enough to encapsulate the chip.