Abstract: Objective To explore change trends of iodine intake and composition among adult residents in Beijing municipality.Methods The data were extracted from two rounds of cross-sectional nutrition study conducted in 2002 and 2012 by China Center for Disease Control and Prevention.Multistage stratified and proportion to population size random cluster sampling were used to select 3 106 and 3 615 residents aged ≥ 18 years for the survey in 2001 and 2012 in Beijing city.The dietary iodine and edible salt intake were worked out by 3 consecutive days of dietary recollection combined with food weighing method.Results The average daily intake of iodine among the adults was decreased from 445.3 μg/day in 2002 to 388.7μg/day in 2012 and the main reason for the decline was the decreased intake of iodized salt from 11.9 g/day to 9.6 g/day which leads to a 80.5 μg decrease in iodine intake.The food intake origination of iodine other than salt was increased from 24.8 μg/day to 49.9 μg/day.Of the adults,17.7% (550/3 106) had the iodine intake higher than the tolerable upper intake level (UL,600 μg/d) and 7.3% (228/3 106) had the iodine intake lower than the recommended nutrient intake (RNI) in 2002;while the proportions of the adults with the iodine intake higher than UL and lower than RNI were 15.6% (563/3 615) and 6.9% (251/3 615) in 2012.There was a significant difference in iodine intake among the adults residing in various areas (F=160.5,P<0.001) in 2012.Conclusion The iodine intake was somewhat high among adult residents in Beijing mainly due to excessive table salt consumption but the intake was decreased obviously along with the implementation of interventions on table salt use.