Activated carbon fiber (C-WACF) with super high surface area and well-developed small mesopores were prepared by liquefied wood and uses wood charcoal (WC) as additive. The characterization and properties of C-WACF were investigated by XRD, XPS and N-2 adsorption. Results showed the pore development was significant at temperatures >750 degrees C, and reached a maximum BET surface area (2604.7 m(2)/g) and total pore volume (1.433 cm(3)/g) at 850 degrees C, of which 86.8% was from the contribution of the small mesopores of 2-4 nm. It was also found that the mesopore volume and methylene blue adsorption of C-WACF were highly increased as the temperature increases from 750 to 850 degrees C. Additionally, the reduction of graphitic layers, the obvious changes of functional groups and the more unstable carbons on the surface of C-WACF, which played important roles in the formation of mesopores, were also observed. (C) 2014 Elsevier Ltd. All rights reserved.