The invention relates to a method for inhibiting broadband background noise in a pipeline-blockage acoustic signal, which comprises the steps of extracting the frequency-domain spectrum of an input oil-gas pipeline-blockage low-frequency echoed signal containing steady broadband background noise, estimating the frequency-domain spectrum of the background noise, and inhibiting the background noiseby utilizing a Wiener filter. Since the Wiener filter is introduced into the invention, the pipeline background noise is eliminated, and the acoustic characteristics of a blockage low-frequency reflection echoed signal are effectively extracted. A system has a good inhibiting action on the slowly-changed broadband background noise, and the false-alarm rate is decreased.