Abstract:The CaCl2-CaF2 molten salt was made by the vacuum dewatering process, and the effects of the dewatering temperature and dewatering time on the H2O and CaO, the influence of the different sizes on the watering absorption and the relationships between the solubility of the metal cerium and the temperatures and time were studied. Results showed: the impurities H2O and CaO contents in molten salt were low under the conditions of the dewatering temperature 500 ℃ and the dewaerting time 5hours, the content of the H2O and CaO of the prepared molten salt was <0.05% and <0.02% separately using the process of the temperature 800 ℃ and the keeping time 2hours. The solubility of the metal cerium in molten salt increased gradually with the increase of molten salt temperatures and dissolution time. The water absorption properties of the different particle sizes molten salt were different obviously, the smaller the molten salt grain, the stronger the water absorption performance.