A practical packaging structure was designed based on the designed MEMS high-g acceleration sensor, and encapsulation performance was simulated when it used potting. By the result of simulation, the packaging structure can meet the requirements that sensor demand, which can test the namal signal under 200,000 g impact load. From the results of modal and static simulation, potting can not only improve the natural frequency of the package model, but also can reduce the stress when shock load effected on the model. Elastic modulus of the potting materials have the great influence on the package performance, but the density has little effect on it. The simulation results also show that the modal frequency of the package model increases with modulus increases, while the the stress reduce when the same load on the package model. However, the modal frequency is much smaller than the packaging structure without potting when the elastic modulus was too small,which may bring a distortion of the sensor output signal.