The present invention provides a high temperature resistant inner layer material for a heat radiator water pipe and a preparation method thereof. The high temperature resistant inner layer material can satisfy cooling liquid aging resistance under the long time action of a high temperature medium, high resistance and no zinc in the material, and can be balanced in the aspects of compression permanent deformation, extension, physical and mechanical properties, low temperature performance, resistance and the like. The high temperature resistant inner layer material includes the following variouspreparation materials: 0-80 parts by weight of ethylene-propylene copolymer, 0-150 parts by weight of ethylene-propylene diene copolymer, 50-150 parts by weight of carbon black, 20-50 parts by weightof a plasticizer, 0-20 parts by weight of precipitation method white carbon black, 0-15 parts by weight of magnesium oxide, 0-2 parts by weight of stearic acid, 1.5 to 8 parts by weight of an antioxidant, 2.5 to 10 parts by weight of crosslinking agent BIBP, 1 to 3.5 parts by weight of crosslinking agent TMPTMA and 1-8 parts by weight of other auxiliaries.