In this study, it use the way of electroless Ni-plated. First of all, it take advantage of gaining the whole Ni ion covered in the polyester woven fabric with oxidation reduction. Then the polyester woven fabric enable the electric conductivity such as aurum. There is a sharp increase the electric conductivity and electromagnetic shielding effectiveness. Last but not least, the electromagnetic corn posite materials are that they mix the epoxy resin with the magnetic filler of Al2O3. In conclusion, we got the excellent electromagnetic shielding effectiveness on condition that the composite materials add Al2O3 of 5%, the electroless Ni-plated temperature of 80℃ and time of 40 minutes.