Carbon nitride nanorods have been synthesized by ball milling method.The graphite powders were first milled for 200 h under the presence of the NH3 gas with 300 kPa.And then they were annealed for 5 h in the ammonia gas flow more than 700℃.The as-synthesized products were characterized by X-ray powder diffraction (XRD),transmission electron microscopy (TEM),electron diffraction (ED),FTIR and electron energy loss spectroscopy (EELS).The diameter of nanorods is in the range of 80—150 nm and the length is about 1—2 μm.The results showed that the structure of the most as-synthesized products were β- C3N4 signal crystal.The optical property of β- C3N4 has been measured by the PL spectra and the computing results showed that the peak is at 3.5—4.4eV which confirmed that β- C3N4 is semi-conduct material with broad band.The growth mechanism of β- C3N4 nanorods is also discussed tentatively.