The synthesis of platelet graphite nanofibers (PGNFs) by the thermal decomposition of mixture contain poly(ethylene glycol) (PEG) and hydrochloric acid (HCl) at 700 degrees C using Ni as a catalyst. The mixture was located in the upstream which PEG was serving as carbon source and HCl serving as accelerant for grown nanofiber. The catalysts were prepared by spin coating nickel acetate solution and oxidation at 700 degrees C. The PGNFs synthesized with mix HCl in carbon source. Electron microscopy revealed the PGNFs is about 60-80 nm in diameter, with a high degree of graphitization, well-ordered graphene layers. The chlorine played an important role in promoted nanofibers grown and formation of PGNFs.