The phase equilibrium and physicochemical properties（density,conductivity and pH value）of the ternary system NaVO3—Na3PO4—H2O were studied at 298 K by the isothermal dissolution method.According to the determined data,the phase diagram and composition-proerties-composition diagram were plotted.The isothermal solubility diagram of the ternary system consists of two univariant curves,one invariant point B,and two crystallization regions for salt Na3 PO>4·8H2O and NaVO3,respectively.No double salt or solid solution is formed.Physicochemical properties（density,conductivity and pH value）regularly change with the composition of solution.
