In this paper, an adaptive temperature demodulation method to eliminate Rayleigh noise real-timely in Raman distributed temperature sensors using anti-Stokes light only has been presented. The theoretical model calculating Rayleigh noise is proposed. Based on known parameters, the Rayleigh noise can be calculated and then eliminated simultaneously by the intensity of the signal composed by anti-Stokes light and Rayleigh noise at two different temperatures. In our experiments, two sections of reference fiber I, II are utilized and their temperatures were set at 27 and 40 ∘C respectively after using this method.