SiC nanopowder has been formed using an original technological approach based on grinding of bulk porous SiC nanostructures. The initial porous SiC nanostructures were obtained by anodization of n+-type 4H-SiC substrate in HF/Ethanol solution under UV illumination. Large single SiC nanoparticles (~ 30 nm in diameter) constituting the nanopowder have a porous structure which can be clearly visible. On the other hand, small single SiC nanoparticles (~ 4 nm in diameter) exhibit a clear crystalline structure. A broad and very intense luminescence band (400 – 900 nm) provided from the nanopowder corresponds to the radiative processes involving nanoparticle surface states. A smaller photoluminescence peak centred at 358 nm may correspond to radiative recombination of the photogenerated excitons confined in the individual and spatially separated 4HSiC nanoparticles.