▎ 摘　　要

Compared with other drug carriers, graphene materials attract more attention due to their large specific surface area, strong targeting and controlled release. Graphene adsorbs anticancer drugs such as doxorubicin and paclitaxel via strong II-II interaction between graphene and the aromatic conjugated structure in drug molecules. The adsorption stability of benzene as minimum aromatic conjugated structure on graphene surface is investigated in this research. The evolution paths of relative stable and unstable positions strongly depend on the size of graphene. For graphene with different size ratios, the evolution paths of benzene go through different stages with decrease of adsorption height and the most stable adsorption position can be found. Based on the interaction energy, the edge effect of graphene with finite size is used to reveal the mechanism of size effect, which is caused by the competition between van der Waals energy and electrostatic energy. This research can provide a reference for the manufacture and application of graphene as drug carriers.