In this work, graphite nanofibers (GNFs) were prepared by ammonia and heat treatment at temperatures up to 1000oC to improve its CO2 adsorption capacity. The effects of the heat treatment on the textural properties and surface chemistry of the GNFs were investigated by N2 adsorption isotherms, XRD, and elemental analysis. We found that the chemical properties of GNFs were significantly changed after the ammonia treatment. Mainly amine groups were formed on the GNF surfaces such as lactam groups, pyrrole and pyridines. The GNFs treated at 500oC showed highest CO2 adsorption capacity of 26.9 mg/g at 273 K in this system.