The invention discloses an antiaging silicon dioxide aerogel polyurethane composite thermal-insulation wallboard which is prepared from the following raw materials in parts by weight: 5-6 parts of magnesium hydroxide whisker, 3-3.5 parts of polyurethane resin, 0.8-1.1 parts of PE (polyethylene) wax, 4-5 parts of nano titanium dioxide, 100-105 parts of porous ceramic ball, 100 parts of water glass, a right amount of Span-80, a right amount of Tween-80, a right amount of 1 mol/L ammonia water, a right amount of acetone, a right amount of ethanol, 90-94 parts of polyether glycol DSU-365, 0.5-0.54 part of triethanolamine, 15-16 parts of water, 0.75-0.9 part of dibutyltin dilaurate and 100-110 parts of polymethylene polyphenyl polyisocyanate. The magnesium hydroxide whisker, polyurethane resin, PE wax and nano titanium dioxide are utilized to enhance the aging resistance, toughness, flame retardancy and heat resistance of the polyurethane foam and prolong the thermal insulation time efficiency.