Three-phase NaCl-H_2O fluid inclusions featuring halite dissolution temperature(Tm)higher than vapor bubble disappearance temperature(T_h) are commonly observed in porphyry copper/molybdenum deposits,skarn-type deposits and other magmatic- hydrothermal ore deposits.Based on |ΔV_1|(the absolute value of volume variation of NaCl-H_2O solution in a heating or cooling process of inclusions)= |ΔV_s|(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 H_2O,we systematically calculated the densities of NaCl-H_2O solutions in the solid-liquid two-phase field for temperatures(T_h) from 0.1℃ to 800℃ and salinities from 26.3 wt%to 99.2wt%.Consequently for the first time we obtained the upper limit of the density of NaCI-H_2O solutions in the solid-liquid twophase field for T_b