The utility model belongs to structure vibration test field, especially relates to a high-sensitivity temperature self-compensation type optical fiber grating low-frequency acceleration sensing device composed of two optical fiber gratings, a rotating shaft, a cross rod, damping liquid, a spring, a mass block and an outer housing. The gratings are respectively connected with the outer housing connecting bar and the cross rod and are engraved on the same optical fiber, the cross rod is used for connecting the rotating shaft and the mass block, two terminals of the rotating shaft are connected with the outer housing, the upper terminal of the spring is connected with the mass block, the lower terminal of the spring is connected with the outer housing, damping liquid is filled in the outer housing. The utility model transfers the vibration of the mass block to the optical fiber gratings by lever principle to result in wave length change thereby obtaining vibration signal of the structure by wave length demodulation. The utility model has high sensitivity, the range scope can satisfy engineering requirement by parameter optimization; the utility model can realizes rigorous temperature self-compensation by two-grating structure; the sensor structure is much more steadily by introducing the rotating shaft, the geometric nonlinear affect can be eliminated, correctness of the signal and durability of the sensor can be reinforced.