Abstract: Aiming at the problems of low processing precision, unstable dimension and easy to absorb water & moisture and corrode the base material in processing, application technology of the multilayer composite foam absorbent material is studied in this paper. The multi-layer structure composition, coating process flow and the change rule of coating size are introduced. An improvement method is put forward that polyurethane membrane system replaces the chloroprene membrane system. The volatile ion composition and microwave absorbing properties of the two kinds of membrane materials are compared by spectroscopic analysis. The environmental adaptability of the improved polyurethane membrane system is proved to be better than that of the chloroprene membrane system by environmental test. This improvement has increased the engineering application value of this kind of microwave absorbing material.