In order to improve the accuracy of the fiber Bragg grating demodulation system,a denoising processing and filtering analysis method based on empirical mode decomposition is proposed.The intrinsic mode functions obtained by EMD are derived into signal component dominanting modes and noise component dominanting modes. Denoising can be achieved by reconstructing the signal using the modes reflecting the main structures of the signal. The experimental results show that the output signal of demodulation system can achieve identitfying the location of central wavelength and the Bragg wavelength shift accurately. The output spectrum has the features of less distortion and higher SNR.The curve fitting of temperature shows that the fitting linearity is 0.998, and the accuracy of demodulation system is greatly improved.