The invention relates to the field of silicone rubber composite processing and particularly relates to high-toughness and high-oil-resistant silicone rubber slurry used for preparing an ultrathin sealing rubber layer and doped with nano carbon and a preparation method thereof. The silicone rubber slurry is prepared from following raw materials, by weight: 5-7 parts of dioctyl phthalate, 1-2 parts of carbon nano tubes, 30-40 parts of methylbenzene, 12-16 parts of mica powder in 400-600 meshes, 1-2 parts of dihydroxydiphenylsilane, 15-18 parts of cyclohexane, 6-9 parts of liquid polysulfide rubber, 1-1.5 parts of maleic anhydride, 22-26 parts of silicone raw rubber, 0.1-0.2 parts of a defoaming agent, 0.5-1 part of 2,5-dimethyl-2,5-bis(tert-butyl-peroxyl)hexane, 0.1-0.2 parts of an adhesive 2260, 4-5 parts of a color master batch, 0.1-0.2 parts of an anti-oxidizing agent and 0.2-0.3 parts of an amino silane coupling agent. Compared with a conventional silicone rubber, the silicone rubber slurry is improved in performances. The mixed slurry is high in stability and is convenient to use in silk-screen printing. A vulcanized rubber layer can be as low as 0.05 mm in thickness, is excellent in toughness and strength, allows secondary processing, is economic and high-effective, is oil-resistant and abrasion-resistant, is durable in sealing effect, and is excellent in sealing effect on oil materials, liquids and such fluids.