Abstract: Objective To understand the influence of taking oral iodized oil capsule on iodine metabolism of lactating women and their infants. Methods A total of 109 lactating women(aged 19-36 years) and their children(aged 20 days-18-months) taking no oral iodized oil capsules within half a year were selected from 4 villages of Yaha township of Kuche county, Aksu to carry out on-site intervention. To detect iodine concentrations in urine and milk, the urine samples were taken from the lactating women and their infants respectively and milk samples were taken from the lactating women at 1, 3, 7, 14, 30, 50, 75 and 100 days. The same samples were also taken from control groups. Results Positive correlations between the urine and milk iodine concentrations of the lactating women and the urinary iodine concentration of the infants was found after statistical analysis(r=0.773,Pr=0.526,Pr=0.389,Pr=0.307,PConclusion It is suggested to increase the dosage or time of oral iodized oil capsule administration due to its short time protection, but whether to shorten this iodine supplement interval in severe iodine deficient area needs further study.