A new structural of the fiber Bragg grating（FBG） pressure sensor based on the semiconductor quartz underlay material is developed and the pressure characteristic of the sensor is experimented.The results show that the centre wavelength of FBG is linear to the pressure.The measured pressure sensitivity of the FBG sensor is about 0.034 nm/MPa and the measuring range is 0

3

5 MPa;The experiment indicates that the sensor has good linearity and repeatability between the centre wavelength of the FBG and pressure change and there is little hysteresis effect

their pertinence coefficient is more than 0.99.It will have the value in the field of the optics sensor.