Abstract: A new type of geophone is presented, based on the narrow band transmission and free of back reflection features of long period fiber grating. The acceleration sensitivity of the resonance wavelength of the long period fiber grating geophone system was deduced and analyzed with the phase matching of long period fiber grating as preconditions. The mechanic model of the long period fiber grating geophone was established and the transfer function of the geophone was deduced. Through simulating a simple example, the amplitudefrequency characteristics of the long period fiber grating geophone was obtained, and its feasibility was proved. The parameters such as length of the optical fiber, the mass of the mass block and the damping factor were improved to achieve proper frequency feature and sensitivity.