Abstract: Objective To understand the iodine nutrition status of children,pregnant women and the progress in the elimination of iodine deficiency disorders (IDD) in Yunnan province after salt iodine content was reduced,and provide scientific evidence for the prevention and control of IDD.Methods According to Evaluation Protocol for the Control and Elimination of Key Endemic Diseases,in all the 129 counties (cities,districts) of Yunnan,5 townships were randomly selected in each county,which locate in the east,west,south,north and middle of the county,4 administrative villages were selected in each township and at least 15 households were selected for the test of salt iodine content.In each township,at least 40 children aged 8-10 years were selected from a village primary school for the detection of urine iodine and goiter,20 pregnant women were selected for the detection of urine iodine and their household salt iodine content.Among the 20 pregnant women,10 were randomly selected for health knowledge awareness survey.Results A total of 38 813 household salt samples were detected,iodized salt coverage rate was 98.98%,which was 90% in 99.22% of the counties,and in 7 counties,the non-iodized salt use rates were 5%.A total of 26 012 urine samples were detected in children aged 8-10 years and the median of urine iodine (MUI) was 207.11 g/L,the rate of urine iodine 50 g/L was 2.52%,and the MUI were 100 g/L in 129 counties;27 999 children aged 8-10 years were checked for thyroid,the goiter rate was 0.61%.The goiter rate was 5% in children in 2 counties.Among 12 988 pregnant women surveyed,the iodized salt coverage rate was 98.92%.The qualified iodized salt use rate was 90% in 92.22% of the counties,and the non-iodized salt use rates were 5% in 7 counties.A total of 13 039 urine samples were detected in pregnant women and the MUI was 156.63 g/L,and the MUI was 150 g/L in 61.24% of the counties;In Yunnan,117 counties (cities,districts) had reached the national goal of eliminating IDD.Conclusion The overall iodine nutrition level of children and pregnant women was appropriate.Up to 90.70% of counties (cities,districts) in Yunnan had already reached the national goal of eliminating IDD.The failure to reach the IDD elimination goal in some areas might be due to the low urinary iodine level of local pregnant women.