Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio (SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 dB higher than that with single wavelength, the Brillouin frequency shift (BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed tech-nique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.