Carbonyl iron particles (CIP) with graded dispersion in polyester are prepared by controlled-sedimentation method for the first time. In order to examine the electromagnetic response of the system, the dispersion configuration of CIP, including the content varying as sedimentation height, is investigated. According to impedance matching theory and graded dispersion experiments of CIP, three kinds of multi-layer graded RAM are designed, and their microwave reflectivity curves are also measured. Experimental results have shown that the graded dispersion with CIP corresponds to well microwave absorbability. In other words, the absorbing band depends on the graded dispersion configuration of CIP in polyester matrix. The most important is that experiments of multi-layer graded RAM proved that the artificial RAMs could show ideal absorbability.