A　physics　model　possessed　of　medium　interlayer　composite　shielding　structure　was　proposed.　The　contrast　experiments　of　monolayer　shielding　structure　and　composite　interlayer　shielding　structure　were　designed　and　carried　out.　The　ΔSE,　the　abbreviation　for　electromagnetic　shielding　effectiveness　increments,　of　composite　interiayer　shielding　structure　was　measured,　while　it　was　confirmed　by　multilayer　electromagnetic　shielding　theory　formulas.　The　electromagnetic　shielding　effectiveness　of　the　composite　interlayer　shielding　structure　materials　is　obviously　superior　to　that　of　the　monolayer　shielding　structure　materials.　The　preparation　of　the　supple　electromagnetic　shielding　materials　possessed　of　composite　interlayer　shielding　structure　was　performed　by　the　method　of　electrochemical　modification.　Terylene　non-woven　and　polytetrafluoroethylene　were　selected　as　research　objects.　The　results　show　that　the　composite　interlayer　shielding　structure-modified　materials　on　synthetic　fibre　can　be　prepared　by　means　of　selecting　objects　and　optimizing　techniques　of　electrochemical　modification,　which　includes　selecting　different　metallic　plating　layers,　adjusting　the　impulse　electroplate　parameters,　plating　time,　temperature　and　pH.　Within　the　incident　frequency　range　from　1　MHz　to　1000　MHz,　this　kind　of　modified　synthetic　fibre　can　meet　different　demands,　and　the　maximum　SE　is　up　to　98　dB.　Not　only　is　the　composite　interlayer　shielding　structure　obtained,　but　also　synthetic　fibre　materials　are　endowed　with　new　electromagnetic　characteristics　by　way　of　the　process　of　metallic　modification.