The solidliquid equilibria relationship in the two ternary systems sodium chloridezinc chloridewater and magnesium chloridezinc chloridewater at 298 K were investigated based on the isothermal dissolution equilibrium method, integrated with the methods of humid residue, X-ray powder crystal diffraction, and density bottle. According to the determined solubility data combined with the humid residue composition and equilibrium solid phase, the phase diagrams of the two systems were depicted. It is concluded that the two isothermal phase diagrams are categorized as a complex type due to the precipitation of double salt between the two inorganic salt components rather than solid solution. Both of them can be divided into three single solid phase crystalline regions and an unsaturated region. Three solid crystalline phase regions in the ternary system NaCl-ZnCl2-H2O at 298 K were saturated with NaCl, ZnCl2, and 2NaCl center dot ZnCl2 center dot 2H(2)O, and those for the ternary system MgCl2ZnCl2H2O at 298 K were deposited for MgCl2 center dot 6H(2)O, MgCl2-ZnCl2-5H(2)O, and ZnCl2. The densities in the equilibrated liquid phase were determined experimentally and simulated by the Laliberte model. As a result, the model can basically describe the density of two electrolytes in an aqueous solution at normal temperature.