Three-phase NaCl-H2O fluid inclusions featuring halite dissolution temperature (Tm) higher than vapor bubble disappearance temperature (Th) are commonly observed in porphyry copper/molybdenum deposits, skarn-type deposits and other magmatic - hydrothermal ore deposits. Based on │ΔVl│ (the absolute value of volume variation of NaCl-H2O solution in a heating or cooling process of inclusions)=│ΔVs│ (the absolute value of volume variation of the halite crystal in a heating or cooling process of inclusions) and on the principle of conservation of the mass of NaCl and H2O, we systematically calculated the densities of NaCl-H2O solutions in the solid-liquid two-phase field for temperatures (Th) from 0.1°C to 800°C and salinities from 26.3 wt% to 99.2wt%. Consequently for the first time we obtained the upper limit of the density of NaCl-H2O solutions in the solid-liquid two-phase field for Th