In this paper, we analyzed and evaluated noise suppression charateristic of EM wave absorber. First, we fabricated several absorber samples in different ratios of Sendust and Amorphous with CPE (Cholorinated Ploy-ethylene) as binder. Secondly, complex relative permittivity and Complex relative permeability was calculated by the measured data. And absorption abilities were simulated according to different thickness of the EM wave absorbers using complex relative permittivity and permeability. The EM wave absorber was fabricated based on simulated data. Simulated and measured value agree well. As a result,, the developed EM wave absorber has a thickness of 2.6 mm and absorption ability over 40 dB at 5.8 GHz.