A set of using arrayed waveguide grating (AWG) for distributed fiber Bragg grating (FBG) wide variation of center wavelength demodulation method is presented. According to the characteristics that AWG center wavelength of each channel can change with the chip′s temperature changes, a voltage control circuit was designed, and the chip′s temperature can vary from 30℃ to 90℃ periodically, several minutes per period. Simultaneously, the data of the channels of AWG can be collected in high speed by a computer. Then the chip′s temperature can be found responding to the maximum of each channel. Finally, the computer can report central wavelength of FBG according the relationship of wavelength and temperature. The experiment demodulating system was established. The experiment results prove that the system can effectively resolve the problem of measurement range. The system can report the central wavelength of FGB in 0.6 nm each channel (40 channels in total) in less than 10 minutes, but also measurement error is less than 2 percent.