In this paper, focusing on the exigent requirement of ultra-thin sound absorption structure in the limited space for noise treatment, the raw material was stainless steel fiber felt, the complex film materials composed with stainless steel fiber porous material and metal film were prepared by low temperature sintering technology. The sound absorption coefficient of complex film materials was tested by B&K acoustic test platform at the frequency range from 50 Hz to 1000 Hz, and the effect of structural parameters on the sound absorption performance of complex film materials is analyzed. The results shown as follows: the effects of pore structure of metal fiber porous materials (pore diameter, wire diameter, sintering node) and number of metal film layers on the sound absorption performance of complex film materials were studied. It is found that in the frequency range of 50 Hz to 1000 Hz, the optimal structure of ultra-thin complex film materials is that the arranged order of the porous metal fiber material is fine wire diameter, small pore facing to sound source, thick wire diameter and large pore in the back. Complex copper-film inside the materials can effectively improve the sound absorption performance at low frequency.