The invention discloses a nano silicon dioxide modified polyurethane composite material comprising the raw materials: polytetrahydrofuran glycol, hydroxyl-terminated polyepichlorohydrin, isocyanate, epoxy resin, a chain extender, 1H,1H,8H,8H-dodecafluoro-1,8-octanediol, a catalyst, polypropylene, a maleic anhydride grafted ethylene-octene copolymer, an acrylonitrile-styrene-butadiene copolymer, ethylene-propylene-diene rubber, organic modified nano silicon dioxide, tetrapod-like zinc oxide whiskers, graphene oxide, carbon nanotubes, expanded graphite, tris(2-chloroethyl) phosphate, triphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, di(octane phenol polyoxyethylene)phosphate, polythiazole, and a silane coupling agent. The nano silicon dioxide modified polyurethane composite material provided by the invention has the advantages of excellent heat resistance, good flame retardancy, good water resistance, and high strength.