The needle punched felt bag adopts the non-woven needle punching process to make use of the fine fiber cloths in which the fibers are staggered and the gaps are distributed uniformly. The surface of the needle felt produced by the polyester staple fiber and the polyester twisted yarns is hot-rolled, singed, or coated After the post-treatment, the surface of the filter bag of the needle felt is smooth and is not easily blocked by dust. The filter bag of the needle felt has a large void ratio, good air permeability, a wide range of uses, strong chemical stability, and can not only filter normal temperature gas. , And can filter the corrosive gas containing acid and alkali, and can filter water, filter oil, is an ideal filter material in normal temperature conditions, liquid-solid separation and other fields. It has the advantages of high void space, good air permeability, high dust collection efficiency and long service life. Acupuncture felt filter bags are moderate in temperature resistance, up to 150°C in instant, moderate in acid and alkali resistance, and have very good abrasion resistance.