The invention belongs to the technical field of civil engineering, and concretely relates to prefabricated heat preservation wall body. The prefabricated heat preservation wall body consists of a heat preservation layer, a concrete internal wall panel, a concrete external wall panel and an FRP connecting piece, the concrete internal wall panel is internally provided with longitudinally arranged steel bars and transversely arranged steel bars, the concrete external wall panel is internally provided with longitudinal arranged steel bars and transversely arranged steel bars, the FRP connecting piece is of a recumbent H structure and consists of a ventral shield and flange girths, two flange girths are provided in the invention and are respectively arranged at the two ends of the ventral shield; the heat preservation layer is arranged between the concrete internal wall panel and the concrete external wall panel and is internally provided with hole slots which are arranged in a crisscross way, and the FRP connecting piece is inserted in the hole slots; the end of the heat preservation wall body is provided with a splice bar which is of a U-shape structure, the two ends of the splice bar are respectively inserted into the concrete external wall panel and the concrete internal wall panel. The invention realizes a novel prefabricated heat preservation wall body with an integral structural function, has the advantages of low heat conductivity coefficient, good corrosive nature, simple and convenient construction and the like, and has relatively extensive application prospect in the field of constructional engineering.