Abstract: Objective To understand the forms of iodine in water in areas with rich iodine in water in China. Methods I2-Starch Spectrophotometry and high performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS) were used to identify the forms of iodine and measure the iodine level in water samples taken from some areas with rich iodine in water in China. Results Among 172 water samples detected, iodine exists in the form of iodide(with a limited amount of iodine molecules) in 161 water samples, both iodate and iodide in 10 water samples and iodate in 1 water sample. Conclusion In some areas with rich iodine in water in China, iodine mainly exists in the form of iodide, followed by both iodide and iodate, iodate form is rare. No sample was found to contain periodate.