Abstract: In order to calibrate the strain stretch coefficient of Bragg grating strain measurement system simply and precisely, on the basis of the analysis of the demodulation principle of the measurement system, we proposed the method for using inverse piezoelectric effect of lead zirconate titanate (PZT) to calibrate the system and carried out the calibration experiment on the 8 strain measurement channels. The relationship curves of the strain and the phase difference between demodulation signals were obtained by the linear fitting of the experimental data of each channel,and the strain sensing coefficient of each channel was determined by the relationship curves. Analysis shows that the coefficients of the calibration relative error is within 0.002 m/（）, the results have higher accuracy.