Abstract: Iodine content in fluoride molten salt was determined by using NaClO oxidation-inductively coupled plasma mass spectrometry(ICP-MS) analysis technology, which is intended to be used to study the iodine behavior in simulated molten salt reactor environment. The results show that ICP-MS can measure the iodine content(in the form of IO^-₃) in FLiNaK salt correctly and reliably after oxidization by NaClO. When the mass of FLiNaK is 0.1 g, the detection limit of the methodology is 0.066 μg/g, the recovery are from 103.1% to 104.3%, and the precisions are less than 6%(n=6). Furthermore, the measurement results obtained by ion chromatography(IC) and ICP-MS followed by NaClO oxidation are consistent, and the latter has the advantages of faster measurement speed and lower detection level. The method of NaClO oxidation-ICP-MS can effectively measure the low content of iodine in fluoride molten salt.