After spinning by adding hexamethylenetetramine and the curing treatment, carbon fibers from liquefied wood (LWCFs) were prepared by direct carbonization. Microstructure change of LWCFs during carbonization is studied by X-ray, Raman spectroscopy, and FTIR. Raman spectroscopy shows both the D peak at 1360 cm(-1) and the G peak at 1595 cm(-1) exist after 600 degrees C, and a significant decrease is found in I-D/I-G during carbonization. X-ray diffraction shows the crystallite size (L-c(002) and L-a(100)) of LWCFs firstly decreases before 800 degrees C and then increases with heat treatment temperature (HTT) increasing, whereas the interlayer spacing (d(002)) gradually decreases during carbonization. It is also found that the crystallite shape (L-a/L-c) and the degree of graphitization (G) all increase with increasing HTT. It is also found that structure of the precursor fibers from liquefied wood has been completely changed after carbonization. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3525-3530, 2011