By measuring the dielectric constant and loss factor of agar gel (99wt%moisture content) containing sodium chloride (concentration: 0. 1, 0. 2, 0. 3, 0. 4, 0. 5, 1, 1. 5,2%) to investigate the effect of salt concentration on dielectric properties of agar gel with high water content was studied. Meanwhile, the possibility to use the dielectric properties of agar gel simulated as real food under microwave heating was discussed in this study as well,which broadens the applicability in studying the temperature distributing of food by thermometry of liquid crystal.