Objective To investigate the iodine nutrition level of vulnerable people in Inner Mongolia after adjustment of iodized salt standard and to provide theoretical bases for scientific iodine supplementation. Methods In 2013, 3 cities were selected from eastern, central and western parts of Inner Mongolia in accordance with the random number table, 3 or 4 counties were selected from each target city, 5 units according to their sub-area position of east, south, west, north and center were selected from each county, and then 1 township was selected from each unit, 5 groups of target population including school children aged 8- 10, women of childbearing age, pregnant and lactating women and infants each at least 10 people were investigated in each township. Edible salt samples from their homes and urine samples were collected. The direct titration method among the generic methods of iodide testing for salt production industry (GB/T 13025.7-2012) was used to determine the salt iodine level, and As3+-Ce4+catalytic spectrophotometry using ammonium per sulfate digestion (WS/T 107-2009) was used to test the urinary iodine level. Results Totally 3 300 samples of edible salt from local residents had been examined and median iodine was 26.20 mg/kg. The median of urinary iodine was 190.6μg/L of 1 289 school-age children;was 183.6μg/L of 621 women of childbearing age; was 178.2 μg/L o f 876 pregnant women; was 178.6 μg/L of 664 lactating women and was 167.7μg/L of 599 infants. Conclusion After adjustment of iodized salt standard, iodine nutrition level is suitable in all vulnerable people.