This study describes the design and implementation of a novel high-performance piezoresistive accelerometer for the measurement of shock acceleration of up to 100 000 g. The structure of the accelerometer sensing chip was implemented with piezoresistive self-support beams. The piezoresistors were made in piezoresistive sensing micro-beams, which were independent of support beams, to weaken the correlation between measuring sensitivity and resonant frequency. In this way, the measuring sensitivity of the proposed novel piezoresistive accelerometer could be increased without sacrificing resonant frequency. The optimization of structural dimensions of the sensing chip was conducted through finite element method simulations. The sensing chip was fabricated employing bulk-micromachining technology with a silicon-on-insulator wafer. The fabricated accelerometer was encapsulated in stainless shell and evaluated using the Hopkinson bar system. Results demonstrated the proposed accelerometer with the measuring sensitivity of 0.54 µV/g/V and the resonant frequency of 445 kHz.