TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Sheet: The flame retardant sheet layer is formed using a composition containing 40 wt.% or more inorganic particles. The inorganic particles are chosen from crystalline mineral silicate, ceramic fiber, alumina powder, gibbsite powder, asbestos fiber, glass fiber and their mixture, preferably mica particles or ceramic fiber. The amount of inorganic particles with respect to total weight of the composition is 60 wt.% or more, preferably 80 wt.% or more. The thickness of flame retardant sheet layer is 30-500 mu m, preferably 50-200 mu m. The average diameter of each hole is 0.3-5 mm, preferably 0.3-3 mm. The interval between the adjacent holes is 1-30 mm, preferably 2-25 mm.    TECHNOLOGY FOCUS - POLYMERS - Preferred Layer: The primary polymer film layer and secondary polymer film layer are formed from a composition comprising a polymer material. The polymer material is chosen from fluorine-containing polymer, polyester, polycarbonate, polyolefin, ethylene copolymer, polyvinyl butyral, norbornene copolymer, polystyrene, styrene-acrylate copolymer, acrylonitrile-styrene copolymer, polyacrylic ester, polyether sulfone, polysulfone, polyamide, polyurethane, acrylic resin, cellulose acetate, cellulose triacetate, cellophane, polyvinyl chloride, vinylidene chloride copolymer, epoxy resin and their mixture, preferably fluorine-containing polymer or polyester. The fluorine-containing polymer is chosen from vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene and their mixture, preferably polyvinyl fluoride. The polyester is chosen from polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate and their mixture, preferably polyethylene terephthalate. The primary polymer film layer is formed using fluorine-containing polymer. The secondary polymer film layer is formed using polyester. The laminated flame-retardant sheet further has a primary adhesive layer formed between primary polymer film layer and flame retardant sheet layer, and/or a secondary adhesive layer formed between secondary polymer film layer and flame retardant sheet layer. The primary and secondary adhesive layers are formed using reactive adhesive and/or non-reactive adhesive. The reactive adhesive is chosen from polyurethane, acrylic resin, epoxy resin, polyimide, silicone resin and their mixture. The non-reactive adhesive is chosen from polyethylene, polyester, and their mixture. The adhesive layers contain adhesive material chosen from ethylene copolymer and polyurethane. The laminated flame-retardant sheet further has additional film or sheet.