Activated carbon(AC) was impregnated with different concentrations of phosphoric acid. The pore structure of purified activated carbon(PAC) and impregnated activated carbons(IACs) was analysed by means of physical adsorption of N2 gas at 77K. The adsorption isotherms of N2 showed a Type I isotherm indicating microporous carbon for allactivated carbons. The specific surface area, pore volume and pore size distribution of 1wt%-H3PO4/AC(PA/AC) took the maximum value, but was slowly decreased with increasing the impregnated H3PO4 content. Also, the effect of the impregnated H3PO4 content on adsorption capacity and the textural properties of PA/AC were investigated. Benzene, toluene, o-, m-, p-xylene, methanol, ethanol, iso-propanol, methylethylketone were selected as model gases. The adsorption performance of the 1wt%-PA/AC was the best. The amount of benzene and p-xylene on 1wt%-PA/AC was increased about 1.5 times and 2 times compared to that on PAC, respectively.