To meet the requirements of vibration sensors in spindle vibration measurement systems, a new micro-electromechanical systems (MEMS) silicon piezoresistive accelerometer with a slotted eight-beam (SEB) structure was designed and developed. The proposed structure was designed to improve the trade-off between the sensitivity and the natural frequency of a piezoresistive accelerometer, which is made possible by incorporating slots into the eight-beam (EB) structure. To obtain the optimal parameters of the designed sensor, the mechanism by which the slot location and size influence the performance of the designed structure was studied and analyzed by finite element simulation (FEM). The developed sensor and EB structure sensor were fabricated on an n-type single-crystal silicon wafer and packaged for an experiment. The accelerometer prototype was tested in a centrifugal machine and a dynamic calibration system. The experimental results show that the sensitivity of the designed sensor is 2.03 mV/g and its natural frequency is 14.16 kHz. Compared with the structure without slots, the sensitivity was increased by 45% and the natural frequency remained basically unchanged.