According to the filtering form, the non-woven filter material has two forms: dry type and wet type. Dry filtration is the separation of floating or suspended solid particles in the gas or dust in the air, which is called bag filtration in industrial production. Bag filter is usually needle punched non-woven fabric filter material. Wet filtration is to separate the floating or suspended solid particles in the liquid, i.e. liquid-solid separation. The filter cloth is used in various types of filters. Generally, Spunlaced non-woven filter materials are used for wet filtration.