Abstract: Carbon fiber precursors were prepared from liquefied wood in phenol by adding hexamethylenetetramine and soaking in the solution containing hydrochloric acid and formaldehyde as the main components. The pryolysis process and dynamics of carbon fiber precursors prepared from liquefied wood were studied using the thermo-gravimetric analysis method. The results show that, the maximum pyrolysis rate of the synthetic fibers occurred at 510℃,and the second pyrolysis reaction caused at 748℃. Because of the less thermal mass loss, it is illustrated thermal stability of the synthetic fibers was good. There were two exothermic decomposition peaks on DSC curves of the synthetic fibers from 0 to 600℃. The location of these peaks move to high temperature with increasing heating rate and the shape of peaks became larger and wider. The activation energy of two peaks were 69.36 and 59.02 kJ/mol, respectively. Reaction order were 0.862 and 0.734, respectively, and less than 1. That showed the two decomposition reactions was relatively complex.