Abstract: Gas chromatography with continuous sample introduction was used in the dynamic testing of adsorbability of active carbon fibre toward toluene. Relationships between the initial breakthrough time and different specific surface area of the active carbon fibre,and between the adsorptive capacity and specific surface area,under the same adsorption condition were studied. The results obtained were compared with those obtained by GC with intermittent sample introduction. Linear relationships were found between increase of values of specific surface area and delaying of the initial breakthrough time,and between increase of values of specific surface area and the simultaneous raising of adsorptive capacity of the toluene tested. These phenomena were used to characterize the difference in specific surface area of the active carbon fibre. In addition,as compared with the mode of intermittent sample introduction,the present method was proved to be simpler in operation and to obtained the breakthrough curve of the active carbon fibre more quickly and efficiently and to describe the breakthrough curve more precisely.