The invention relates to a heat-preservation pipe shell and a mounting method thereof. The heat-preservation pipe shell structurally comprises a bottom layer heat-preservation structure, a middle layer heat-preservation structure and an outer layer heat-preservation structure in sequence from inside to outside; reinforcing base material structures are arranged on the inner surface and the outer surface of each layer of heat-preservation structures for fixing heat-preservation layers; and concave-convex modules are arranged at the two ends of each layer of heat-preservation structures, thus thetwo heat-preservation pipe shells can be mutually buckled tightly, and the heat-preservation effect is good. A sliding device and a rolling body are arranged between the two ends of the bottom layerheat-preservation structure and a high-temperature pipeline, the overall heat-preservation pipe shell can be supported to slide on the high-temperature pipeline, the heat-preservation pipe shell can be precast in advance, on-site construction, mounting and dismounting are quick and safe, and the labor intensity, the construction risk and the maintenance cost of on-site construction can be reduced;and a thin air layer is arranged among the bottom layer heat-preservation structure of the heat-preservation pipe shell, the high-temperature pipeline and the sliding device, thus the energy saving effect is greatly improved, the problem that the heat-preservation layer is excessively thick is solved, and the heat-preservation cost can be lowered reasonably.