The theory of optical fiber accelerometer was represented, and the radial strain ΔR of node in external radius of fiber-optical accelerometer was obtained by the finite element method and the acceleration sensitivity of 39.69dB(0dB=1rad/g)was simulated by the theoretical formula. According to the structure and material parameters obtained from simulations, it is constructed a fiber-optical vector hydrophone, and the experimental results show that the acceleration sensitivity is 39.43dB which is only 0.26dB lower than the simulation result.It is indicated that using the finite element method to analyze the acceleration sensitivity of fiber optic accelerometer is practicable and can provide an important theoretical guiding significance on the structure design and wide application of push-pull type fiber-optic accelerometer.