In order to obtain impact data of armour-piercing cannonball double steel targets penetration, a MEMS high g piezoresistive accelerometer which has a four-end clamped beam - island structure was developed. Chamfers were added at root and end of the microcantilever to increase the intensity of the structure. The intensive encapsulation method which using modified epoxy resin with the stainless steel shell to enhance accelerometer anti overload ability．An integrated high overload test device was designed which was composed of a high-g accelerometer and a high overload electronic memory recorder with a special buffer structure. From the experimental results, peak value of 430000 g in process of penetrating was obtained, and the first layer overload was up to 83281g and the second layer overload peak reached 115185g when low pass cut-off frequency is 10 kHz. This work demonstrated that the accelerometer is an ideal high overload test instrument which can provide an important reference for the related engineering design and practice.