Refractory polycrystalline alumina fiber blanket is made from a refractory fiber composed of γ-alumina/mullite crystal phase, which is produced by the "sol-gel" method to prepare spinning precursors. The precursors are then processed into embryonic cotton through spinning technology, and finally made into a blanket-shaped product through calcination and other processes. It can resist temperatures of up to 1600 ° C and has a low thermal conductivity. It can withstand abrasive chemical conditions and is resistant to chemical corrosion. Used in high-temperature pipeline insulation, furnace lining, and applications such as ceramic manufacture, aerospace, and the production of steel and ceramics.