For the air spinning OE21S pure cotton yarn, we adopt Xinjiang Level-III pure cotton, with high configuration, no knot after electric cleaning, good evenness, little hairiness, selected three strands and safe bleaching and dyeing, which may be used for weaving and knitting and are suitable for making terry yarn, fleece yarn, towel, jean, high-grade clothing fabrics, etc. The cotton yarn has hygroscopic function, moisture retention, heat resistance, alkali resistance and high hygiene.