In order to eliminate the influence of the F-P filter temperature characteristics on the accuracy of the fiber Bragg grating wavelength demodulation system, a method is put forward that uses the F-P etalon as a wavelength reference to calculate the wavelength. A high precision fiber Bragg grating wavelength demodulation system is designed, and the algorithms for filtering, peak detecting and wavelength calculating are achieved by LabWindows/CVI. The experimental results show that the repeatability error is smaller than 1.56 pm, and the stability error is smaller than 1.13 pm.