A new type of symmetrical demodulation method is proposed for the distributed fiber Raman temperature sensor. The anti-Stokes scattering optical time domain reflectometer (OTDR) curves are demodulated by Rayleigh optical time domain reflectometer curves. Firstly, the measured temperature scope is divided into several regions; secondly, when the temperature is obtained by the traditional demodulation method, it will be located on the relative region; then the temperature is demodulated by the region's demarcated temperature, even-number values of temperature are obtained, and the average value is taken as the measured value. The temperature precision and stability of the sensor is improved, with temperature precision error in ±0.05 ℃ and spatial resolution of 1 m. The experimental results agree well with the theoretical ones.