Ta obtain fundamental informations for fine tungsten carbide powders, the preparation of fine tungsten carbide by vapor phase reaction of WCI_6-CH₄,-H₂ system has been carried out in the temperature range of 1000-1400℃. The effects of reaction conditions on particle size and morphology of tungsten carbide powders have been investigated by utilizing X-ray diffraction, SEM and TEM technique . The synthesis temperature of only WC powders is above 1350℃ in the condition of the flow rate of argon and Hz gas is 220㎖/min respectively and CH₄, gas 40㎖/min. `The particle size of the reaction products obtained at 1400℃ is about 0.02㎛ and the shape of WC is spherical. Temperature dependence of the particle size is weak and the lattice parameters a and c decrease gradually with increasing reaction temperature. Also the crystallite size increases gradually with increasing reaction temperature.