Abstract: It is difficult and costs much to treat the printing and dyeing wastewater with extremely high mass concentration cyanide in it using thiosulfate.3R-O purification and recycling technology,independently developed by Changchun Gold Research Institute Company Limited,is used to treat printing and dyeing wastewater.The results show that the total cyanide mass concentration decreases from 7 520 mg/L to less than 50 mg/L,the cyanide removal rate exceeds 97.5 % while most of the cyanide is recycled with the recovery rate 99.1 %.The 3R-O purification and recycling technology treating printing and dyeing wastewater achieves satisfactory economic and environmental benefits.