Carbon nanotubes (CNTs) prepared by catalytic degradation have been treated using the methods of acid, graphitization and acid combined with high temperature graphitization seperatly. The original and heat-treated CNTs were analysed by the transmission electron microscopy and Raman spectroscopy. The results showed that graphitization and acid boiling had obvious effects on eliminating amorphous carbon at surface and enhancing the crystalline degree of CNTs . While the combination of two approaches of treatment showed better effects for enhancing the crystalline degree of CNTs.