The invention belongs to the technical field of reactor structure design, and particularly relates to an irradiation shielding thermal insulation structure. The structure is installed in a closed cavity defined by a refueling pool, a ring beam and a reactor pressure vessel and comprises an irradiation shielding material, an efficient thermal insulation layer and cladding. The efficient thermal insulation layer covers the side, close to the reactor pressure vessel, of the irradiation shielding material, and the irradiation shielding material and the efficient thermal insulation layer are integrally packaged in the cladding. The temperature of the irradiation shielding material and the heat loss of the reactor pressure vessel can be effectively reduced, and high-temperature failure of the irradiation shielding material is avoided; irradiation passing can be hindered, the irradiation dose of a reactor plant operation platform is reduced, and the activation level of structural equipment isreduced.