In view of the problems such as high rate of false positives,susceptibility to electromagnetic interference, not easy to achieve a large area network and long-term reliable remote monitor ing of the traditional electric-type vibration sensor in perimeter intrusion monitoring system,a low frequency fiber Bragg grating (FBG) vibration sensor based on uniform strength beam is designed and studied in this pa per.On the basis of uniform strength beam vibration theory,the FBG vibration tuning principle by uniform st rength beam is derived. Combined with practical engineering applications,the uniform strength beam stru cture size and vibrator mass of the sensor are optimized.Using ANSYS software,the first-order resonanc e frequency of the FBG vibration sensor is calculated,which is 94.74Hz.Two different vibration sources with 35Hz and 50Hz excitation frequencies are used to test the FBG vibration sensor.According to the experime ntal data and frequency domain analysis,the results show that this sensor could achieve accurate frequency tes t for the vibration sources,with good response characteristics to meet the special requirement of perimeter intrusion monitoring system in military fields.