In this paper, the temperature dependence of stacking of graphite layer during the heat treatment
process for carbon fiber was investigated by the method of 2-dimensional wide angle X-ray diffraction (WAXD). The
results indicated that with the increas of the treatment temperature, the number of the stacked graphite layer was increased.
When the temperature was higher than 1900℃, the increasing of the stacked layer number was accelerated
due to the improving of defect resulted from the removing of non-carbon elements and the transition to sp2 hybridization,
which was supported by the evidence of Raman spectroscopy and elemental analysis experiments data.