The invention relates to a heat-resistant and high-damping polyurethane elastomer, which is prepared from the following raw materials by weight: 27.92%-33.56% of polytetramethylene glycol, 8.52%-9.03% of diphenyl-methane-diisocyanate, 26.02%-31.66% of polycaprolactone diol, 9.02%-9.70% of 1, 4-cyclohexane diisocyanate, 0.10%-0.30% of N, N'- dicyclohexylcarbodiimide, 4.91%-5.62% of neopentyl glycol, 0.06%-0.10% of dibutyltin dilaurate, 0.60%-0.90% of carbon nanotube, and 15.02%-15.45% of nano-silica, with the sum of the weight percentage of the components being 100%. The preparation method includes: weighing raw materials, preparing an acidified carbon nanotube, preparing a nano-silica dispersion solution, preparing a polyurethane elastomer prepolymer A, preparing a polyurethane elastomer prepolymer B, preparing a chain extender-carbon nanotube/neopentyl glycol composite hydroxyl component, preparing a polyurethane elastomer casting liquid, and preparing the heat-resistant and high-damping polyurethane elastomer by means of tape-casting. The method provided by the invention can solve the problem of poor heat resistance of polyurethane elastomers in the prior art, and the prepared polyurethane elastomer has high heat resistance and high damping property.