Soils in different depths were collected in a site, the effect of adding 5%(m/m)activated carbon on polycyclic aromatic hydrocarbons (PAHs) residues in soils was studied by an incubation experiment, and the changes of bioavailability of PAHs in soils was evaluated using the hydroxypropyl-β-cyclodextrin extraction method. The results show that the residues of phenanthrene, pyrene and benzo[b]fluoranthene in the soils treated with activated carbon are significantly higher than in the control treatment, but there is no significant difference in the residues of benzo[g,h,i]pyrene in soils between the two treatments within eight months. During the first month, the bioavailability of phenanthrene, pyrene and benzo[b]fluoranthene in activated carbon treatment are decreased by 35.06%, 37.73% and 39.60%, respectively compared with the control treatment, and the bioavailability of benzo[ghi]pyrene is decreased by only 1.37%. With the extension of incubation time, the inhibition effect of activated carbon on PAHs bioavailability in soil is decreased. Therefore, this study shows that amending 5% activated carbon can effectively reduce the bioavailability and environmental risk of PAHs in contaminated soil, especially during the first month of treatment.