There are mainly bromine indigo (commonly known as emerald blue) denim and vulcanized black denim, as well as coffee, emerald, gray, khaki, vulcanized blue denim with sulphur dyed color, and a small amount of natto dye or reactive dye. Dyed red, pink, ochre denim, etc., although the production volume is not large, but the market demand is more urgent, often can not meet the needs. The main problem is that the color shade is not stable enough, the dyeing attention is also poor, and the garment manufacturer is not satisfied. This is of course related to the small production volume and excessive color, but it is more difficult to produce white color by the dyeing combined machine. Large, high cost, and difficult to treat sewage, etc., also have a certain impact. The first solution is to minimize the number of color combinations in the design, use two color combinations as much as possible, no more than three color combinations, or replace them with other stable dye varieties to adapt to the production characteristics of the dyeing line. Stable dyeing effect; Secondly, the more thorough solution is to use dyed factory yarn for large-capacity dyeing, and the production process of slitting and warping to produce white denim.