The invention discloses a valve sealing gasket sizing material, which is prepared from the following raw materials in parts by weight: 20-30 parts of fluorosilicone rubber, 50-60 parts of hydrogenated nitrile-butadiene rubber, 15-25 parts of chlorosulfonated polyethylene rubber TS-320 (TOSOH, Japan), 2-3 parts of gamma-methacryloxypropyltrimethoxysilane, 1-2 parts of diphenyl silandiol, 14-16 parts of modified tree ash, 2-3 parts of ferrocene, 0.2-0.6 part of dicumyl peroxide (DCP), 20-30 parts of high-abrasion resistant carbon black N330, 20-25 parts of precipitated white carbon black, 5-7 parts of light calcium carbonate, 2-4 parts of zinc oxide, 1-3 parts of calcium stearate, 1-3 parts of aluminium oxide, 5-8 parts of dolomite, 13-15 parts of modified iron tailing powder, 0.1-0.3 part of accelerating agent MBTS, 1-2 parts of sulphur, 1-2 parts of anti-aging agent RD, 1-2 parts of anti-aging agent MB, 1-2 parts of benzimidazole-2-thiol, 1-3 parts of methyltrimethoxy silane, and 2-3 parts of paraffin. The sizing material of the rubber has excellent high and low temperature-resistant, oil-proof, solvent-resistant and chemical-resistant performance, and at the same time is good in mechanical property and low in cost.