The invention relates to the field of high molecular materials, in particular to a high-temperature-resistant polyvinyl chloride modified material and a preparation method. The high-temperature-resistant polyvinyl chloride modified material at least comprises, by weight, 80-110 parts of polyvinyl chloride resin, 8-25 parts of modified urea resin, 0.5-5 parts of acrylic, 40-60 parts of plasticizers, 4-10 parts of benzhydrazide derivatives, 12-35 parts of filling agents, 0.1-0.8 part of lubricant, and 0.5-3 parts of fire retardants. The degree of polymerization of the polyvinyl chloride resin is 1000-2000. The plasticizers are epoxy-plant-oil based plasticizers. The lubricant is an amides-type lubricant.