A novel fiber Bragg grating(FBG) based seismic sensor is presented in this paper.The FBG seismic sensor head consists of FBG,spring and mass.The mechanical model is demonstrated.The amplitude-frequency and acceleration characteristics of the FBG seismic sensor are theoretically analyzed.The main factors affecting the sensitivity are also given.The experimental results show that the FBG seismic sensor system has excellent stability and high durability.The frequency response range is from 10 Hz to 140 Hz,the resonant frequency is 167 Hz,and the acceleration sensitivity of the FBG seismic sensor is 25.4 pm/g,Which agree with the theoretical values.The maximum detected acceleration is larger than 30 g.