In this paper,the principle of a pendulous large range accelerometer is introduced,by means of classical control theory the mathematical models of every parter of the accelerometer are set up.

According to structure characteristics and problems in the existing mold of the plug base, analyzed the mold structure, as well as secondary ejection structure by tension plate pendulum block was established, in addition, solved the problems of internal surface of the plug base becoming dark and out surface having burr.