The fibrous porous metals as a noise control material was used in harsh environment which in the high temperature, strong vibration, high sound intensity, corrosion, etc. But the effects of porosity and wire diameter on sound absorption performance in different thickness were waiting for lucubrated. In this paper, fibrous porous metals which the thickness were from 1mm to 30mm were prepared by three kinds of sintering processing, loose sintering, compacting sintering, positioning sintering. The absorption coefficient was tested by double microphone impedance measurement tube of B&K Company in Denmark. The effects of the porosity and the wire diameter were studied systematic. The results shown that there was a different optimum range value of porosity with different thickness, for example, the zone of the thickness from 1mm to 3mm, the porosity in the range from 80% to 85%, and the thickness was 5mm, the porosity in the range from 85% to 90%, and the zone of the thickness from 10mm to 15mm, the porosity in the range from 90% to 94%, the sound absorption performance was the best at the frequency from 50Hz to 6400Hz, which was increased with thickness. When the wire diameter ≤3mm, the smaller the fiber diameter, the sound absorption performance was very good in the whole frequency, when the thickness from 3mm to 20mm, with the thickness increased, the sound absorption performance of the materials in thicker diameter was well gradually, the absorption peak was moved to low frequency, the sound absorption performance at high frequency was still kept very well, and when the wire diameter ≥20mm, the larger the fiber diameter, the sound absorption performance was very good in the whole frequency.