Nanocrystalline ZrN has been successfully prepared via benzene-thermal reaction of ZrCl4 and NaN3 at 350-380 degrees C. X-ray powder diffraction patterns indicated that the crystallinity of ZrN was considerably high and the cell constant was a = 4.567 Angstrom. Transmission electron microscopy images showed the powders consist of uniform spherical particles with a narrow particle-size distribution (10-20 nm). The role benzene-solvent played in the formation of nanocrystalline ZrN was discussed.