In order to obtain the electromagnetic shielding material, the lightweight flakes of poplar are selected to be the substrate. After the electroless copper plating, the flakes turn to electric cell which is made by hot-press with bicomponent epoxy, and it turn to electromagnetic shielding materials. In this paper, the electromagnetic shielding effectiveness of electromagnetic shielding materials is investigated. The results indicates that the reasonable ratio of main components of the electroless copper plating is: copper sulfate 80g/L, reducing agent 90 g/L, K-Na tartrate (TART) 65 g/L, EDTA•2Na100 g/L, α, α'-dipyridyl 10mg/L, potassium ferrocyanide 50 mg/L. In the testing of Hertzian waves between 9 kHz～1.5GHz, the average effectiveness of electromagnetic shielding is 60.4dB.