The nuclear power industry of China has the features of large scale and rapid development in recent years. The status monitoring system of nuclear power units has an urgent need for high temperature and radiation resistant piezoelectric accelerometers with independent intellectual property rights. According to the characteristics of acceleration signal in nuclear power environment, a compressive piezoelectric accelerometer with radiation resistance is proposed and designed in this paper. At the same time, the working principle of the sensor is introduced, its mathematical model is deduced, and the structure of the sensor is optimized by ANSYS finite element simulation platform. The relationship between the output performance and structure parameters of accelerometer sensor is investigated by the simulation experiment. The simulation results show that the optimal output voltage variation of accelerometer sensor is ±0.85% and the amplitude of the output voltage is greater than 11mV when the thickness of piezoelectric ceramics is 0.8 mm, the thickness of mass block is 3.5 mm, the diameter of screw is 1.8 mm, the diameter of central hole is 2 mm and the external diameter of ceramics is 4.4 mm. The accelerometer sensor has high sensitivity and low stress intensity, which lays the foundation for developing high performance status montoring systm of nuclear power units of China.