Air component of brick firing furnace is quite complex, including both the fuel vapor harmful gases produced by combustion and water evaporation produced by body, as well as alkali metal ions existing in the raw materials. Since refractory fiber has a very large surface area, when the water vapor presents in the air, refractory fibers will absorb a lot of moisture. At the same time, the carbon dioxide and silicon dioxide in furnace medium can dissolve in water, forming weak acid. Weak acid and alkali ion fiber can take replacement reaction, thereby undermining the fiber structure, and it will lead to the fibers’ erosion and deterioration in long-term use. Alkali metal ions and aluminum silicate refractory fibers can react and result in feldspar, destroying the fiber’s network structure. Under reducing atmosphere, fiber crystallization will accelerate, reducing the fiber’s life. These harmful gases and substances will react with refractory fiber, corroding refractory fiber, destructing of its original structure, which caused refractory fiber’s pulverization,shrinkage and breakage. It is also one of the important reasons accounting for the usage life of furnace.