A thermal insulation member, comprising inorganic fiber prefabricated components having different grading temperatures, wherein the inorganic fiber prefabricated components having different grading temperatures are combined according to the grading temperatures in descending order and are fixedly connected together. Each inorganic fiber prefabricated component is a unit module body (9). Both ends of the unit module body (9) are additionally equipped with protective clamping plates (10). The outer surfaces of the module body (9) and the clamping plates (10) are provided with strapping tapes (11). After the improvement based on the prior art, a low-cost low temperature layer (2) is used for a non-high temperature resistance surface of a furnace wall. Therefore, use costs are further reduced.