Abstract: A Ag/AgCl reference electrode with pyrex glass and porcelain diaphr agm for use in LiCl-KCl-NaCl molten salt system at 480°-600℃ is described.In order to ensure a long periodic stability of the reference electrodefor hygroscopic molten salts a pyrex glass or porcelain tube conductive to sodium ions should be used as a diaphragm;besides,the water arid the oxygen in the molten salts should be removed thoroughly and the assembled electrode should be sealed perfectly.The experimental results show that EMF of the reference electrode with pyrex glass diaphragm was stable and reproducible to within 5 mv,as well as temperature and current-reversible cycling over a period of 110 hours.The inflenence of temperature and cdncentrat-on of AgCl to the electrode potential also has been discussed.It is shown that the concentration of AgCl chosen within 2-4 mol% may be better.