Nanocrystalline SiC films have been synthesized on Si(111) substrate by hot filament chemical vapor deposition(HFCVD) technique with CH4 and SiH4 as reaction gases.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM) and photoluminescence(PL) spectroscopy are used to investigate the structure,morphology and PL of the films respectively.Results from these techniques show that the films deposited at relatively low substrate temperature contain SiC nanocrystalites,with an average dimension of about 6 nm,embedded in an amorphous SiC matrix.The visible-light emitting in the wavelength range between 400 nm and 550 nm has been observed from the nanocrystalline films excited by a HeCr laser at room temperature.