Abstract: Objective The study was conducted to determine the iodine nutrition status of the involved population in the seriously endemic area of iodine deficiency through urine iodine tests for pregnant and breast-feeding women in Wushi and Baicheng County. Methods Ammonium persulfate digestible -arsenic-cerium catalyzed spectrophotometry was used to detect single random urine of the pregnant women and lactating women, and the results were statistically analyzed using SPSS15.0. Results A total of 338 urine samples were tested. As a result, the median urinary iodine was 180.96 g/L, the inter-quartile range 229.385 g/L. There were 65 samples with iodine 50 g/L, accounting for 18.6%; 121 samples with iodine 100 g/L, accounting for 35.8%; and 150 samples with iodine 150 g/L, accounting for 44.4%. 18.9% of pregnant and breastfeeding women had the urinary iodine in the range of 150-250 g/L. Conclusion A proportion of 44.4% of the key population had insufficient iodine nutrition in the iodine deficiency area of Xinjiang. Effective and targeted measures to supplement the iodine should be taken promptly in light of the local conditions to prevent mental retardation caused by iodine deficiency.