Activated carbons were prepared from Chinese fir wood by phosphoric acid activation.The lignocellulosic precursor impregnated with phosphoric acid was pre-treated at low temperature in the 80-160 ℃ range.The crystallinity index and surface chemistry of the pre-treated samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR).The porous texture of activated carbon was investigated by N2 adsorption-desorption isotherms.The results showed that the pre-treatment with heating at low temperature can affect the final properties of activated carbon significantly.With the increasing of heating temperature,under the effect of acid-catalyzed hydrolysis,the crystallinity of lignocellulosic materials decreased and gave rise to the development of pore,especially the micropores.When the heating temperature is 140 ℃,the microporous percentage of activated carbon reaches a maximum,the value is 97.2%.However,excessively high pre-treated temperature is not benefit for activation.FT-IR showed that with the pre-treated temperature increasing,the aromaticity of pre-treated samples increased and the aliphatic character lost.Thus,pre-treatment at low temperature may be regarded as an excellent method for manufacturing activated carbon with high micropore volume.