Abstract: The fiber Bragg grating (FBG) demodulation system based on the traditional matching FBG technology has the disadvantages of low wavelength matching accuracy, difficult wavelength adjustment and small dynamic measurement range. To overcome these disadvantages, a novel wavelength demodulation technology of fiber grating is proposed by using a tunable Gaussian filter instead of the conventional matching fiber grating. A vibration demodulation system using fiber grating is established based on the Gaussian filter. The vibration demodulation experiments are conducted for periodic vibration with different frequencies and amplitudes. It is found that, when the Gaussian filter with a suitable bandwidth is selected, the optical power of the light passing through the filter varies synchronously with a high fidelity as the voltage signal applied to the PZT varies. This indicates that the system demodulates the vibration signals effectively. Also, this system features high response speed,simple physical framework and large dynamic measurement range.