Objective To study the clinical significance of monitoring the urine iodine level in pregnant women.Methods The urine iodine levels were detected in 391 cases of pregnant women.The relativity was analyzed among the pregnancy gestation,pregnancy complications and the urine iodine levels.The corresponding health educa-tion of iodine nutritional knowledge was conducted according to the results of the determination.Results (1 )The urine iodine value was (124.73 ±70.61)μg/L in 391 pregnant women.The severe deficiency iodine rate,deficiency iodine rate and appropriate iodine rate of pregnant women were 37.85%,64.70% and 25.06%,respectively.(2) There was no significant difference in values of urine iodine among the pregnant women during the first,second and third trimester of pregnancy[(121.76 ±71.81)μg/L,(125.52 ±69.28)μg/L,(129.30 ±75.19)μg/L](t≤0.59, all P >0.05).The mean values were all lower than the appropriate values of WHO(150 ~249 μg/L).The low iodine rates were 67.20%,63.23% and 65.12%,respectively.There was no significant difference among them(χ2 =0.56, P >0.05 ).(3 )The urine iodine value of the pregnant women complicated with hyperthyroidism [(85.76 ± 53.09)μg/L]was significantly lower than that of primary hypothyroidism combined with pregnancy [(133.65 ± 73.41)μg/L],pregnancy combined with subclinical hypothyroidism[(136.50 ±79.19)μg/L]and no pregnancy complication[(119.34 ±66.43)μg/L](t≥2.76,P <0.01).The rate of iodine deficiency(87.88%)was highest (χ2 =8.72,P <0.05).(4)The urine iodine value after iodine nutrition intervention was significantly higher than those before in 77 pregnant women[(129.74 ±68.04)μg/L vs.(107.01 ±74.36)μg/L,t =1.98,P <0.05].The iodine deficiency rate dropped from 79.22% to 63.64%(χ2 =4.58,P <0.05).Conclusion In order to improve the appropriate iodine rate of pregnant women,it should be very important significance on monitoring the urine iodine level of pregnant women in particular with a complication of pregnancy and conducting iodine nutrition intervention in whole pregnancy gestation.