Commercially activated carbon was treated with 1mol/L nitric acid, 1mol/L sulfuric acid and 1mol/L hydrochloric acid respectively. The physicochemical properties of these modified activated carbons were described with Boehm titration, Fourier transformed infrared spectroscopy (FTIR) and BET surface area measurement. Fixed-bed adsorption experiments were conducted under the same experimental conditions at 283K, where toluene was activated as adsorbates. Adsorption capacity on modified activated carbons was conducted, combining the calculation of dynamics and adsorption energy. The results have shown that the total amount of acid groups increased after acid modification and the pore size distribution is different from the unmodified activated carbon. The adsorption capacity of toluene on acid modified activated carbon shows the following order: N-AC，S-AC，AC， Cl-AC. The pseudo-second-order kinetic equation is better than the pseudo-first-order kinetic equation to describe the adsorption process of toluene on the modified activated carbons. Acid modification can increase the percentage of micropore and enhance the rate of adsorption. With the increase of adsorption energy, it is hard for the modified activated carbons to join toluene.