An integrated three-dimensional acceleration sensor based on fiber Bragg grating (FBG) was presented in this paper. The sensor took the cross-beams as the elastomer, and the strain distribution characteristics of the elastomer were studied by using the finite element analysis method. Five FBGs were encapsulated on the surfaces of the beams according to specific rules. The difference of wavelength shifts of pairwise FBGs was used as the output signal of the sensor in different vibration directions to realize low coupling measurement of three-dimensional acceleration and temperature compensation. The vibration test results show that: the resonant frequencies of the sensor in the x, y, and z directions are 2000, 1920, and 1160 Hz, respectively; the operating frequency bands are 20?1400 Hz, 20?1300 Hz, and 10?800 Hz, respectively; the sensitivities in the x, y, and z directions are 1.36, 1.70, and 1.31 pm/g, respectively. Moreover, the sensor has good linearity, weak coupling, and temperature compensation capability.