The yarn uses the self-developed non-aqueous media eco-friendly dyeing technology, which uses silicon-based media to replace water in the dyeing process, dyeing does not need to add salt to promote dyeing, reactive dye color retention rate can reach 90%, and the number of washing times after washing is greatly reduced. Solve the problem of waste water from cotton yarn dyeing at the source. For each ton of black cotton yarn dyed, non-aqueous medium dyeing technology compared with traditional water bath dyeing, the amount of salt reduce from 800kg to 0kg, the amount of dye reduce from 50kg to 40kg, and the amount of sewage production reduce from 73 tons to 36 tons. At the same time, through the water reuse technology, the wastewater generated by non-aqueous media dyeing can be fully recycled, and zero waste water discharge can be achieved. Fabric color spectrum is complete, the color fastness of dark fabric is excellent.