The invention provides a preparation method of a thermal insulation coating high-performance polyurethane elastomer. After the reaction of terminal hydroxyl polybutadiene liquid rubber and polyisocyanate, polyurethane is added for reaction for 3 to 4.5 hours at 85 to 90 DEG C to produce isocyanate-terminated prepolymer; a certain amount of heat insulating filler is added in the prepolymer and is mixed evenly to produce component A; chain extender, antioxidant, curing agent and solvent are mixed evenly according to a certain portion to produce component B; the component A and the component B with the weight portion of 3: 1 to 6: 1 are mixed, stirred evenly, cured at room temperature to produce the thermal insulation coating high-performance polyurethane elastomer. The process of the invention used to synthesize the thermal insulation coating high-performance polyurethane elastomer is more reasonable, the product has higher quality and better comprehensive properties. The test date shows that the tensile strength is 3.50 to 5.80MPa, the elongation at break is more than 220 percent, the bond strength is more than 10.0MPa, the glass transition temperature is less than 60 DEG C below zero, the solidification shrinkage rate is less than 0.1 percent. The product is mainly applicable to aerospace industry.