When the filter cake layer is not formed at the initial stage of the use of conventional filter materials, it mainly depends on the interception effect of the fiber itself. When facing ultra-fine and small particles, the capture ability is poor. Polytetrafluoroethylene microporous membrane is covered on the surface of filter material through adhesive or high temperature hot pressing technology. Because the particle size of dust particles is much larger than that of micropores covered with membrane, particles are directly intercepted on the surface of microporous membrane. The filtration efficiency is very high and is very suitable for the field of high-precision filtration.