The shell of the gas tempering furnace is welded by steel plates and sections. The bottom of the furnace body is made of high-alumina mullite. The top of the furnace is made of a vacuum high-pressure full-fiber module structure, which saves about 60% of energy compared to a brick furnace. The amount of compression to ensure that after the completion of the module, each ceramic fiber block expands in different directions, so that the modules are extruded into a gap-free whole, to achieve a good heat storage effect, and the product is convenient and quick to construct, all can It is directly fixed on the stainless steel anchor round nail of the steel plate of the furnace shell. Compared with other products, it has the advantages of low thermal conductivity, low heat capacity, excellent corrosion performance, excellent thermal stability and thermal shock resistance, thermal insulation, and the anchor is set on the cold surface of the furnace body, which improves the high temperature strength of the fiber.