Polystyrene/silicon　wrapped　ammonium　polyphosphate/reduced　graphene　oxide　(PS/SiAPP/rGO)　composites　with　satisfactory　flame　retardant　and　electromagnetic　interference　(EMI)　shielding　properties　were　prepared　by　the　approaches　of　filtration　induced　assembly　and　hot-pressing.　The　results　indicated　that　the　SiAPP　and　rGO　exhibited　good　dispersivity　in　the　PS　matrix.　The　introduction　of　the　SiAPP　and　rGO　promoted　the　thermal　and　fire-safe　performances　of　PS　composites.　Moreover,　the　peak　of　heat　release　rate　and　total　heat　release　of　the　PS　containing　10 wt%　SiAPP　and　10 wt%　rGO　were　reduced　by　47.2%　and　30.3%,　respectively.　Meanwhile,　the　EMI　shielding　performance　could　reach　10 dB.　It　was　proposed　that　that　the　SiAPP　and　rGO　promoted　the　formation　of　more　continuous　and　compact　char　residues　besides　the　capture　of　free　radicals,　that　is,　•H　and　•OH　which　improved　the　flame　retardant　performance　of　PS.　In　addition,　the　multiple　reflect　and　adsorption　contributed　to　enhanced　EMI　shielding　property.　Therefore,　the　assembled　PS/SiAPP/rGO　system　will　offer　a　new　approach　to　broaden　the　application　of　PS.　©　2021　John　Wiley　&　Sons　Ltd.