In this study, the main purpose is analyzing the absorbance of electromagnetic wave. The double layers have three dimensional effect structure and fluffy, and the angle of direction would influence the performance of electromagnetic absorption. The yarn with different composition, with 5%, 10%, 20%, 100%, knitted to form a sheet as a screen of monolayer electromagnetic absorbers. The results showed the performance of double layer-sheet is much more than monolayer sheet. And the high absorbance of electromagnetic wave is 40dB.