The methodology of radioisotope induced X-ray fluorescence analysis (XRF) of thyroid iodine was studied. According to the basic principle
a combined system with an excitingt source and a counting device was designed. Experiments on the method for measuremen-and experimental arrangement were carried out. The reliability
sensitivity as well as expo-sure-dose were discussed. XRF examination was performed in 12 cases with normal thy roid. The results showed that thyroid iodine can be determined directly with this way.