In order to improve the measurement sensitivity of the beam structure fiber grating vibration sensor,a cantilever beam structure fiber grating vibrat ion sensor was designed and proposed.Firstly,the working principle of the fibe r grating vibration sensor with the cantilever beam structure is analyzed theore tically.Secondly,the relationship between the length of the cantilever beam an d the effective length of the fiber grating in the structure and the natural fre quency and sensitivity is simulated,so that the sensor can obtain higher sensit ivity.The simulation results show that the natural frequency gradually decrease s with the increase of the effective length of the fiber grating,but the sensit ivity increases with the increase of the cantilever beam length.When the effect ive length of the fiber grating increases,the natural frequency and sensitivity of the fiber tend to decrease.According to theoretical analysis and simulation results,the optimal parameters of the ‘E’ beam structure and the effective l ength of the optical fiber were finally determined,which was well verified in e xperiments.The experimental results show that the flat area of the sensor is 15 Hz~60 Hz,its natural frequency is 83 Hz,and the sensitivity is as high a s 481.32pm/g.The good performance of the vibration sensor in the detection of vibration signals will have important research significance in the field of vibration sen sing such as bridges and buildings.