In response to the requirement of high-precision measurement of the low-freque ncy vibration signal,a variable width elliptical hinged low-frequency acceleration sensor based on double fiber Bragg gratings is designed in this paper.Firstly,the structure mo del of the sensor is established,the vibration response characteristics of the sensor are analyze d theoretically, and the resonant frequency and sensitivity formula of the sensor are given.Then the mathematical model of sensor unit is established,and the key dimension paramete rs of the sensing unit structure are optimized.In addition,the theoretical analysis resu lts are verified by finite element simulation.Finally,the sensor sample is manufactured and its ac celeration performance is tested.The experimental results show that the resonance frequenc y of the sensor is 36Hz,while the working frequency band is 0－10Hz,in which the sensitivity is 1496pm/g. The designed sensor has high sensitivity,and temperature compensation ability, which can be used for low-frequency vibration measurement.