Abstract: A geometrical acoustical method is used and put forward a physical model that backscattering of a tube is simplified into reflection of a plane wave on layered media under high frequency,far field,thin tube,to set up reconstruction formulas of the parameters of a metallic tube with sound-absorbing materials covered.The internal and external radii of a aluminium tube and the tubber covered thickness are reconstructed by using simulatied sound fields and experiment.The theoretical results obtained by this method are supported by experiments.