Industrial wastes have exerted high loads on environment in view of the difficulties to reserve landfill space and the risk of air pollution. In this study we proposed a method of simultaneous disposing of inorganic waste and common organic waste, in light of cascade recycling concept. Zeolite-carbon composite was synthesized by a combination of calcinations and hydrothermal treatment of coal fly ash and sawdust mixtures. The microstructure, phase compositions and electromagnetic wave absorption properties of the composite were evaluated. The results showed that the low cost composite has the potential to be used as high value-added humidity-controlling building material with the ability to absorb electromagnetic wave.