Polycrystalline alumina fiber wet process products is made by using the "sol-gel" technology to form a slurry from high-purity alumina. Then, the slurry is made into fiber-shaped material through the special technology, and then processed into alumina fiberboard through processes such as pressing, drying, and sintering. It has excellent properties such as high temperature resistance, corrosion resistance, thermal insulation performance, and mechanical strength.