The density of molten Ni-W alloys was measured with a modified pycnometric method. It is found that the density of the molten Ni-W alloys decreases with temperature rising, but increases with the increase of tungsten concentration in the alloys. The molar volume of molten Ni-W binary alloys increases with the increase of temperature and tungsten concentration. The partial molar volume of tungsten in liquid Ni-W binary alloy has been calculated approximately as (-1.59+5.64×10 -3 T)×10 -6 m3·mol -1 . The density of molten Ni-W alloys was measured with a modified pycnometric method. It is found that the density of the molten Ni-W alloys decreases with temperature rising, but increases with the increase of tungsten concentration in the alloys. The molar volume of The partial molar volume of tungsten in liquid Ni-W binary alloy has been calculated approximately as (-1.59 + 5.64 × 10 -3 T) × 10 -6 m3 Mol -1.