Aiming at the unclear mechanism of the effect of high and low temperature environment on the sensitivity of high-g accelerometer, a mathematical model of the sensitive unit with a solid support at both ends is proposed. The relationship among the sensor sensitivity, longitudinal stress, and transverse stress of the sensitive unit is determined. The relationship between sensor sensitivity and temperature is obtained by thermal-force coupling simulation analysis. In the range of -40℃ ~ 50℃ , the sensor sensitivity decreases with the increase of temperature, and the sensitivity changes fast in the range of - 40℃ ~ 20℃ . It is slow in the range of 20℃ ~ 50℃ . The sensor sensitivity data under high and low temperature environment are collected by the sensor high and low temperature test. The magnitude of sensitivity at - 40℃ is 0. 523 μV/ g, the magnitude of sensitivity at 50℃ is 0. 516 μV/ g. The experiment results are compared with the simulation results to evaluate the effectiveness of temperature change on the sensor sensitivity law. For improving the measurement accuracy of high-g accelerometer under high and low temperature environment, it has theoretical reference significance.