Abstract: Three-dimensional finite element method is developed to predict and analyze the acoustic attenua-tion characteristics of perforated tube silencers. Comparisons of transmission loss predictions with experimental results for straight-through perforated tube silencers and three-pass perforated tube silencer illustrated that the finite element method can predict acoustic attenuation characteristics of perforated tube silencers accurately. The finite element method is then used to investigate the effects of geometrical parameters on the transmission loss of three-pass perforated tube silencer. The duct extensions into the chambers lead to lower resonant frequencies. To improve the low frequency acoustic attenuation of typical three-pass perforated tube silencer, end-resonator may be added on the right side of three-pass perforated tube silencer.