The experiment for measuring Brillouin shift of optical fiber was set up. The Brillouin shift of a dispersion-shifted fiber was experimentally investigated in the range of 20 to 820 ℃, and the data was fitted. When the environment temperature changes in a wide range, the measured data when fitted by a linear relation, will bring about large errors. We set out our study on the basis of the structure and material properties of fused silica, including the thermal expansion coefficient, the density, the refractive index, the Young’s modulus, and the Poisson’s ratio. The mathematical model for the temperature dependence of each of the parameters was built up. Based on the relationships between Brillouin shift and the material properties, the Brillouin shift has been formulated as a second-order polynomial of temperature over a wide temperature range. Compared with our experimental results, the theoretical results are in good agreement, which lays a foundation for the wide-range Brillouin distributed temperature sensor.