The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system (RDTS) is analyzed in detail, and a simple correction algorithm is proposed to compensate the fiber position error caused by the wavelength dispersion. The principle of the proposed algorithm is described theoretically, and the correction on each point along the entire fiber is realized. Temperature simulation results validate that the temperature distortion is corrected and the temperature accuracy is effectively improved from ±5 ℃ to ±1 ℃.