The ePTFE air filter membrane is made of PTFE resin, through a special process, two-way stretching, using the unique node fibrillation of the PTFE film, smooth surface, chemical resistance, air and water impermeability, large air permeability, flame retardant and resistant With the characteristics of high temperature, strong acid and alkali resistance, non-toxicity, etc., the products made have high filtration efficiency, low running resistance, fast filtration speed, long service life, and reusable use, thereby reducing operating costs.