Abstract: The structures and stabilities of Au_nAl(n=1~8) clusters were investigated using density functional theory at the PW91 level. By optimizing the geometric configuration of clusters, the ground-state Au_nAl(n=1~8)clusters possess two-dimensional structures for n=1~3 and three dimensional for n=4~8. The relative stabilities of the ground-state Au_nAl clusters were analyzed based on the averaged binding energies(E_b), second-order difference of energies(Δ² E), and HOMO-LUMO energy gaps(HLG). The results show that Au₆ Al possesses higher chemical activity and Au₃ Al possesses higher stability.