Abstract: Aiming at the problems of potential gas leakage and dust explosion in coal mine underground pipelines，we proposed a pipeline safety monitoring method based on Ｒ-OTDＲ ( Ｒaman Optical Time DomainＲeflectometry) distributed optical fiber temperature sensor，and analyzed the technical principle of Ｒ-OTDＲ fiber． For the problem of temperature signal noise interference during the acquisition process，the two methods of moving average filtering and EEMD( Ensemble Empirical Mode Decomposition) are used for denoising． The simulation results show that the best noise reduction effect can not be obtained by using one method alone． This paper will combine the sliding average filtering and EEMD denoising algorithm，and use three indicators for effect determination． The experimental results show that the first moving average EEMD can effectively remove the interference noise in the signal，which greatly improves the signal-to-noise ratio and system measurement accuracy． Compared to the traditional algorithm，the system sensing efficiency is higher．

Key words: coal mine underground, distributed optical fiber sensing, denoising algorithm, signal to noise ratio, smoothness