During the construction of urban tunnel project, the noise generated by construction will have a serious impact on the nearby residents. Since the ultra-low frequency noise penetrating power is very strong, normal silencing measures can’t effectively eliminate the effects of ultra-low frequency noise. Aiming at ultra-low frequency tone for 0~20 Hz, the propagation law and acoustic characteristics of ultra-low frequency acoustic waves in a pipeline are analyzed. It is found that the hollow long tube in the pipeline can be used for twice to eliminate the ultra-low frequency sound wave. The first elimination of noise is the principle of mutual interference and cancellation by incident and reflected acoustic waves. Based on the continuity condition of the acoustic wave in the pipeline, the ultra-low frequency acoustic wave is shortly circuited at the nozzle of the long pipe. The second elimination of noise is the principle of energy attenuation, when sound waves travel through pipes of varying cross sections. According to the above theory, a movable and pumping type ultra-low frequency noise silencer is designed, which can effectively eliminate the ultra-low frequency noise produced during the tunnel construction.