We propose an elliptical spring-based three-axis fiber Bragg grating (FBG) accelerometer fabricated by appropriately arranging and encapsulating three identical one-axis sensing structures in a cylindrical shell. The derived theoretical equations and the established simulation model of the sensing structure are in good agreement with the experimental results. Sensors on three axes operate in a frequency band of 10–70 Hz; the sensitivities of the proposed accelerometer in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula> directions are 1197.82, 1157.78, and 1223.04 pm/g, respectively, showing high sensitivity, good consistency, directional response, and resistance to transverse interference.