Preparation and characterization of sodium-graphite intercalation compounds were investigated. It was confirmed that the resulting compound (NaCx) had the stage 8 structure with identity period of 2.8 nm. The Raman spectroscopy showed that the G-band signal of NaCx was observed at 1582 cm(-1) and at 1608 cm(-1) , which is a typical indication of the formation of intercalation compounds. The g-value of NaCx was determined to be 2.0018 by the ESR measurement, which was very close to the reported values for the other alkali metal-graphite intercalation compounds. The electrical resistivity of NaCx was about 1/3 of that of host graphite at room temperature and showed metallic temperature dependence.