In recent years, geophysical detecting technologies develop increasingly in fields, such as petroleum and natural gas exploration, safety alert of ground and coast, target detection in the ocean and underground pipeline monitoring. To realize high precision detection of low-frequency geophysical signals, a novel kind of geophone based on fiber Bragg gratting (FBG) with symmetrcal push-pull structure is designed. In-depth studies are made on structural theories, simulation analysis, optimization design and three-dimensional structure. Results show that the geophone has high sensitivity up to 765.6 pm/g, and dynamic response character of 1~120 Hz is good. Furthermore, it has the function of temperature self-compensation, good direction characters, and can easy to realize three-dimensional structure. So the geophone has the ability of detecting low-frequency geophysical signals.