Tungsten carbide nanocrystal had been prepared by the simple reaction of WO3, Mg, and anhydrous CH3CH2OH in an autoclave at 600 degrees C. There were two types of tungsten carbide in the samples; one was pure WC, and the other was wrapped by carbon. Transmission electron microscopy (TEM) results revealed that the diameters of WC nanocrystals ranged from 100 to 200 nm, and that the WC nanocrystals were slightly agglomerated. The possible formation mechanism of the as-obtained tungsten carbide was discussed.