Objective To monitor the iodine nutrition of pregnant women in Anhui Province from 2018 to 2020,and to master the iodine nutrition level of pregnant women,so as to provide a basis for guiding scientific iodine supplement and improving the overall iodine nutrition level of pregnant women,so as to consolidate the elimination of iodine deficiency disease. Methods The household edible salt and urine of pregnant women in the first, second and third trimesters of pregnancy at 6 provincial monitoring points from 2018 to 2020 were collected, and the contents of salt iodine and urine iodine were determined by iodized salt titration and arsenic cerium catalytic spectrophotometric determination of urine iodine. Results A total of 1 803 pregnant women were investigated.The mean age was (28.7±5.0) years old and the mean gestational age was (23.7±9.5) weeks.Among them, 361 (20.0%), 748 (41.5%) and 694 (38.5%) were pregnant in the early, middle and late stages, respectively.A total of 1 796 household salt samples were collected from pregnant women,including 164 non-iodized salt and 61 unqualified iodized salt.1 791 urine samples were collected from pregnant women,the median of urinary iodine was 154.4 μg/L,869 pregnant women (48.5%) had urinary iodine value <150 μg/L.There were statistically significant differences in iodized salt coverage (χ²=68.563,P<0.001),qualified iodized salt consumption rate (χ²= 43.057,P<0.001),median salt iodine of pregnant women (H=88.639,P<0.001),median urinary iodine of pregnant women (H=73.796,P<0.001),and urinary iodine frequency distribution (χ²=105.052,P<0.001) in different years.The median urinary iodine of the monitored subjects in the early,middle and late pregnancy at the six monitoring points was 153.4 μg/L,161.3 μg/L and 145.0 μg/L.There was no significant difference in the median urinary iodine in different pregnancy periods (H=2.992,P=0.224).The distribution of urinary iodine frequency in different pregnancy periods was statistically significant (χ²=15.365,P=0.043). Conclusion From 2018 to 2020,the rate of non iodized salt consumption by pregnant women has increased year by year,and the iodine nutrition level of pregnant women is generally at a suitable level.Some pregnant women have a high proportion of iodine nutrition deficiency and iodine deficiency in the third trimester.