Objective:This study aims to provide scientific evidence for scientific iodine supplementation through monitoring the iodine nutrition status of children aged 8 - 10 and pregnant women in Haikou City.Methods:From 2016 to 2020, monitoring sites were selected in Longhua, Meilan, Qiongshan and Xiuying districts of Haikou City according to the requirements of the "Hainan Iodine Deficiency Disorders Monitoring Program". The iodine contents of drinking water, household edible salt and urinary iodine contents of children aged 8 - 10 and pregnant women were determined and analyzed.Results:The median iodine content of 388 drinking water samples was 5.60 μg/L, the median salt iodine content of 6 000 household edible salt samples was 25.70 mg/kg, the coverage rate of iodized salt was 98.65% (5 919/6 000), the qualified rate of iodized salt was 98.36% (5 822/5 919) and the consumption rate of qualified iodized salt was 97.03% (5 822/6 000). The median urinary iodine content of 4 000 children aged 8 - 10 was 181.68 μg/L and the median urinary iodine content of 2 000 pregnant women was 130.70 μg/L.Conclusions:The external environment of Haikou is iodine deficient. The iodine nutrition of children is generally in an appropriate state, and that of pregnant women is generally insufficient. While implementing the salt iodization policy, we should strengthen the monitoring of iodine nutrition among people and spreading iodine nutrition knowledge among residents, providing classified guidance and scientific iodine supplementation, so as to achieve the goal of continuous elimination of iodine deficiency disorders.