Abstract: <FONT face=Verdana>Phase equilibria in the NaCl-SrCl2-H2O ternary system at 25 ℃ was studied by using isothermal dissolution equilibrium method.Density and refractive index etc.of the balanced solution were also determined.Phase diagram of NaCl-SrCl2-H2O ternary system was plotted according to experimental data.Diagram was made up of one invariant point,two univariant curves,and two crystallization regions of NaCl and SrCl2?6H2O.In the invariant point,composition of the liquid phase was confirmed,i.e.mass fraction of NaCl was 7.40% and mass fraction of SrCl2 was 29.42%;and corresponding balanced solid phase was NaCl and SrCl2?6H2O.Neither double salts nor solid solutions between the original NaCl and SrCl2?6H2O were found;dehydration of SrCl2?6H2O didn′t occur in the system;and the system was a simple eutectic type.</FONT>