The invention provides a method for measuring the temperature of an inflammable and explosive article based on an optical fiber grating temperature sensor. The method comprises a sensing step and a demodulating step. In the sensing step, the optical fiber grating temperature sensor is adhered to a critical position of the inflammable and explosive article by an adhesive tape, variation of the temperature of the inflammable and explosive article is input into a sensing system, and the wavelength of the optical fiber grating temperature sensor is modulated according to the variation of the temperature. In the demodulating step, optical signals output by the optical fiber grating temperature sensor directly enter a collimating lens, and enter a volume phase grating after being collimated, diffraction and dispersion of multi-wavelength light are generated, light with different wavelengths is separated by the volume phase grating and forms diffraction bands, the diffraction bands are finally focused and irradiated to different positions of a photoelectric detector by a condenser, the optical signals with different wavelengths are detected and converted into electric signals, and the electric signals are output by an electric processing unit. The method has the advantages of high sensitivity, electromagnetic resistance, simple principle, good durability and the like when used for measuring the temperature.